As filed with the Securities and Exchange Commission on March 16, 2021

Registration No. 333-            

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

COGENT BIOSCIENCES, INC.

(Exact name of registrant as specified in its charter)

200 Cambridge Park Drive, Suite 2500

Cambridge, Massachussetts 02140

(617) 945-5576

(Address of Principal Executive Offices, Zip Code)

Cogent Biosciences, Inc. 2018 Stock Option and Incentive Plan

Cogent Biosciences, Inc. 2018 Employee Stock Purchase Plan

(Full title of the plans)

Andrew Robbins

President and Chief Executive Officer

200 Cambridge Park Drive, Suite 2500

Cambridge, Massachussetts 02140

(617) 945-5576

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Sean C. Feller

Gibson, Dunn & Crutcher LLP

2029 Century Park East, Suite 4000

Los Angeles, CA 90067

(310) 552-8500

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☒

CALCULATION OF REGISTRATION FEE

EXPLANATORY NOTE

This Registration Statement on Form S-8 is filed by Cogent Biosciences, Inc. (the “Registrant”) relating to additional shares of its common stock, par value $0.001 per share (the “Common Stock”), available for issuance pursuant to the 2018 Plan and the ESPP. The information contained in the Registrant’s registration statements on Form S-8 filed on March 26, 2020 (Registration No. 333-237406), March 28, 2019 (Registration No. 333-230559) and April 4, 2018 (Registration No. 333-224137), together with all exhibits filed therewith or incorporated therein by reference, is hereby incorporated by reference pursuant to General Instruction E to Form S-8.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

SIGNATURES

Pursuant to the requirements of the Securities Act, the Company certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Boston, State of Massachussetts, on March 16, 2021.

KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Andrew Robbins and John Green, and each of them severally, as his or her true and lawful attorneys-in-fact and agents, with full power of substitution and resubstitution, for him or her in his or her name, place and stead, in any and all capacities, in connection with the Registration Statement, including to sign and file in the name and on behalf of the undersigned as director or officer of the Company (1) any and all amendments or supplements (including any and all stickers and post-effective amendments) to the Registration Statement, with all exhibits thereto, and other documents in connection therewith, and (2) any and all additional registration statements, and any and all amendments thereto, relating to the same offering of securities as those that are covered by the Registration Statement that are filed pursuant to Rule 462(b) promulgated under the Securities Act with the Commission and any applicable securities exchange or securities self-regulatory body, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite or necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents or any of them, or their substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this Registration Statement and the foregoing power of attorney has been signed below by the following persons in the capacities and on the dates indicated.

Exhibit 5.1

March 16, 2021

Cogent Biosciences Inc.

200 Cambridge Park Drive, Suite 2500

Boston, Massachussetts 02140

Ladies and Gentlemen:

We have examined the Registration Statement on Form S-8 (the “Registration Statement”) of Cogent Biosciences, Inc., a Delaware corporation (the “Company”), to be filed with the Securities and Exchange Commission (the “Commission”) pursuant to the Securities Act of 1933, as amended (the “Securities Act”), in connection with the offering by the Company of up to 1,418,916 shares of the Company’s Common Stock, par value $0.001 per share (the “Shares”). The Shares are to be issued under the Cogent Biosciences, Inc. 2018 Stock Option and Incentive Plan and the Cogent Biosciences, Inc. 2018 Employee Stock Purchase Plan (collectively, the “Plans”).

In arriving at the opinions expressed below, we have examined originals, or copies certified or otherwise identified to our satisfaction as being true and complete copies, of the originals, of such documents, corporate records, certificates of officers of the Company and of public officials and other instruments as we have deemed necessary or advisable to enable us to render the opinions set forth below. In our examination, we have assumed without independent investigation the genuineness of all signatures, the legal capacity and competency of all natural persons, the authenticity of all documents submitted to us as originals and the conformity to original documents of all documents submitted to us as copies.

We have also assumed that there are no agreements or understandings between or among the Company and any participants in the Plans that would expand, modify or otherwise affect the terms of the Plans or the respective rights or obligations of the participants thereunder. Based upon the foregoing, and subject to the assumptions, exceptions, qualifications and limitations set forth herein, we are of the opinion that the Shares, when issued and sold against payment therefor as set forth in the Plans, will be validly issued, fully paid and non-assessable.

We consent to the filing of this opinion as an exhibit to the Registration Statement. In giving these consents, we do not thereby admit that we are within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations of the Commission.

Exhibit 23.1

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form S-8 of Cogent Biosciences, Inc. of our report dated March 16, 2021 relating to the financial statements, which appears in Cogent Biosciences, Inc.’s Annual Report on Form 10-K for the year ended December 31, 2020.