Mitsui Chemicals : 【Timely Disclosure】Notice Regarding Change of Representative Directors and Structure of Members of the Board / Audit and Supervisory Board Members

Company name: Mitsui Chemicals, Inc.

HASHIMOTO Osamu,

February 5, 2026

Name of representative:

Representative Director and President (Securities code: 4183 :Prime Market)

Inquiries:

TAKATAMA Yoshinori,

General Manager of Corporate Communications Division (Telephone: ＋81-3-6880-7500)

Mitsui Chemicals, Inc. ("the Company") hereby announces that, at its Board of Directors meeting held today, the Company resolved to change its Representative Directors and structure of Members of the Board / Audit and Supervisory Board members effective on or after April 1, 2026 as described below.

1. Change in Representative Directors

   1. The reason for the change

      To further accelerate the execution of our key strategies-including the transformation of our business portfolio to achieve our Long-Term Business Plan "VISION 2030"-and to drive the Group's sustainable growth and enhancement of corporate value, we will implement changes in Representative Directors and revise our management structure.

   2. Change details (As of April 1, 2026)

      Name	New Position	Current Position
      HASHIMOTO Osamu	Representative Director, Member of the Board, Chairman	Representative Director, Member of the Board, President & CEO
      ICHIMURA Satoshi	Representative Director, Member of the Board, President & CEO	Member of the Board, Managing Executive Officer

   3. Career Summary of the newly appointed Representative Director

      As outlined in 3, "Profiles of newly appointed Members of the Board and Audit and Supervisory Boad Member".

2. Changes in structure of Members of the Board / Audit and Supervisory Board Members

   We will revise the structure of our Members of the Board and Audit and Supervisory Board Members as outlined below. Furthermore, in order to enhance the effectiveness of our corporate governance, we plan to increase the number of Outside Members of the Board by one, subject to approval at the 29th Annual General Meeting of Shareholders scheduled for June 24, 2026 (hereinafter, "the June 2026 AGM"). As a result, the proportion of Outside Members of the Board and Outside Audit and Supervisory Board Members

   (7) will account for half of the total number of Members of the Board and Audit and Supervisory Board Members (14).

   1. Structure of Members of the Board / Audit and Supervisory Board Members (As of April 1, 2026)

      Position	Name	Current Position
      Representative Director, Member of the Board, Chairman	HASHIMOTO Osamu	Representative Director, Member of the Board, President & CEO
      Representative Director, Member of the Board, President & CEO	ICHIMURA Satoshi	Member of the Board, Managing Executive Officer
      Representative Director, Member of the Board, Senior Managing Executive Officer	HIRAHARA Akio	The same as above
      Member of the Board	TANNOWA Tsutomu (NOTE)	Member of the Board, Chairman
      Member of the Board	ANDOU Yoshinori (NOTE)	Member of the Board, Senior Managing Executive Officer
      Outside Member of the Board	MABUCHI Akira	The same as above
      Outside Member of the Board	MIMURA Takayoshi	The same as above
      Outside Member of the Board	KIHARA Tami	The same as above
      Full-time Audit and Supervisory Board Member	NISHIO Hiroshi	The same as above
      Full-time Audit and Supervisory Board Member	HOSOMI Yasuhiro	The same as above
      Outside Audit and Supervisory Board Member	GOTOH Yasuko	The same as above
      Outside Audit and Supervisory Board Member	ONO Junshi	The same as above
      Outside Audit and Supervisory Board Member	KIKUCHI Shin	The same as above

      (NOTE) TANNOWA Tsutomu and ANDOU Yoshinori will retire from their positions as Members of the Board at "the June 2026 AGM".

   2. Structure of Members of the Board / Audit and Supervisory Board Members (As of June 24, 2026) (NOTE1)

      Position	Name	Current Position
      Representative Director, Member of the Board, Chairman	HASHIMOTO Osamu	Representative Director, Member of the Board, President & CEO
      Representative Director, Member of the Board, President & CEO	ICHIMURA Satoshi	Member of the Board, Managing Executive Officer
      Representative Director, Member of the Board, Senior Managing Executive Officer	HIRAHARA Akio	The same as above
      Member of the Board, Managing Executive Officer (Newly appointed)	OMOTE Toshihiko	Managing Executive Officer
      Member of the Board, Managing Executive Officer (Newly appointed)	YOSHIDA Osamu	Managing Executive Officer
      Outside Member of the Board	MABUCHI Akira	The same as above
      Outside Member of the Board	MIMURA Takayoshi	The same as above
      Outside Member of the Board	KIHARA Tami	The same as above
      Outside Member of the Board (Newly appointed) (NOTE2)	SHU Ungyong	-
      Full-time Audit and Supervisory Board Member	HOSOMI Yasuhiro	The same as above
      Full-time Audit and Supervisory Board Member (Newly appointed)	FUNAKOSHI Hiromitsu	Executive Officer, Business Sector Vice President of Basic & Green Materials

      		Business Sector
      Outside Audit and Supervisory Board Member	GOTOH Yasuko	The same as above
      Outside Audit and Supervisory Board Member	ONO Junshi	The same as above
      Outside Audit and Supervisory Board Member	KIKUCHI Shin	The same as above

      (NOTE1) Members of the Board and newly appointed Audit and Supervisory Board Member are scheduled to assume their positions subject to approval at "the June 2026 AGM". The Skill Matrix about this structure is as described in the Appendix.

      (NOTE2) SHU Ungyong does not satisfy the Company's Independence Standards for Independent Outside Directors and Independent Outside Corporate Auditors, as The Core Value Management, Inc. for which he serves as representative, previously had certain business dealings with the Company, we have determined that his expertise in M&A strategy, financial and capital policy, together with his extensive experience as a corporate executive at financial institutions, is indispensable for the strategic oversight of our Company. Accordingly, he is being nominated as an Outside Director as defined in Article 2, Item 15 of the Companies Act.

   3. Career summaries of newly appointed Members of the Board and Audit and Supervisory Board Member As outlined in 3, "Profiles of newly appointed Members of the Board and Audit and Supervisory Boad Member".

3. Profiles of newly appointed Members of the Board and Audit and Supervisory Boad Member

   1. Newly appointed Representative Director

      Name (Birthday)	Career Summary	Number of Shares of the Company Owned
      ICHIMURA Satoshi (January 4, 1967)	April 1992 Joined the Company January 2004 Manager, Ammonia Sect, Manufacturing Dept.-2, Osaka Works October 2012 Director, Business Planning Department, Planning & Coordination Div, Functional Chemicals Business Sector October 2014 Director, Vision Care Materials Department, Health Care Materials Div, Functional Chemicals Business Sector April 2019 General Manager, Planning & Coordination Div, Health Care Business Sector April 2021 Senior Director, General Manager, Planning & Coordination Div, Health Care Business Sector April 2022 Senior Director, General Manager, Corporate Planning Div. April 2023 Executive Officer, General Manager, Corporate Planning Div. April 2024 Managing Executive Officer, CSO, In charge of Corporate Planning Div, Corporate Sustainability DIV, Corporate Sustainability Committee and Risk Management Committee April 2025 Managing Executive Officer, CSO, In charge of Corporate Planning Div, and Risk Management Committee June 2025 Member of the Board, Managing Executive Officer, CSO, In charge of Corporate Planning Div, and Risk Management Committee (to present)	9,484 (Note)

   2. Newly appointed Directors