A series of thiazolidine-2-one derivatives were synthesized by a three-component reaction of carbon dioxide, hydrogen sulfide, and propargyl amines under mild conditions. The simultaneous incorporation of carbon dioxide and hydrogen sulfide into the same organic product was realized. Moreover, a reaction mechanism was proposed based on the detailed NMR and FTIR study, which indicated that propargyl amine reacted with CO 2 first to form carbamate, followed by O/S exchange with H 2 S to form thiocarbamate and the final cyclization of thiocarbamate to form thiazolidine-2-one.