Electronically excited CS2 (CS2) is found to be rapidly produced in the troposphere from the absorption of solar photons by ground state CS2 molecules. The chemical reaction of CS2 with O2 can, if the CS+SOO yield is greater than 0.01, remove tropospheric CS2 on a time scale of one or two weeks. Assuming a ground level background CS2 concentration of 20 pptv and an OCS lifetime of 1 year, calculations indicate that this photooxidation mechanism can be a major source of tropospheric OCS but only a minor source of SO2.