Page 1

Use these links to rapidly review the document TABLE OF CONTENTS INDEX TO FINANCIAL STATEMENTS Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 20 - F ( Mark One ) 0 REGISTRATION STATEMENT PURSUANT TO SECTION 12 ( b ) OR ( g ) OF THE SECURITIES EXCHANGE ACT OF 1934 ý 0 0 OR ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to OR SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of event requiring this shell company report Commission File Number 001-39179 Addex Therapeutics Ltd ( Exact name of registrant as specified in its charter and translation of registrant's name into English ) Switzerland ( Jurisdiction of incorporation or organization ) Chemin des Mines 9 , CH- 1202 Geneva , Switzerland ( Address of principal executive offices ) Tim Dyer Chief Executive Officer Addex Therapeutics Ltd Chemin des Mines 9 , CH - 1202 Geneva , Switzerland Tel : +41 22 884 1555 ( Name , Telephone , E - mail and / or Facsimile number and Address of Company Contact Person ) Securities registered or to be registered pursuant to Section 12 ( b ) of the Act . Title of each class Trading Symbol Name of each exchange on which registered American Depositary Shares , each representing 6 ordinary shares , CHF 1.00 per share ADXN The Nasdaq Stock Market LLC