Gelesis (CPSR) 10-Q 2021 Q2 Quarterly report

EXHIBIT 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of Capstar Special Purpose Acquisition Corp. (the “Company”) on Form 10-Q for the quarterly period ended June 30, 2021, as filed with the Securities and Exchange Commission (the “Report”), I, R. Steven Hicks, Chief Executive Officer and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. §1350, as added by §906 of the Sarbanes-Oxley Act of 2002, that:

1. The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2. To my knowledge, the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company as of and for the period covered by the Report.

Dated: August 13, 2021

/s/ R. Steven Hicks

R. Steven Hicks

Chief Executive Officer and Chief Financial Officer

(Principal Executive Officer and Principal Accounting and Financial Officer)

A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

The foregoing certification is being furnished solely pursuant to 18 U.S.C. Section 1350 and is not being filed as part of this report or as a separate disclosure document.