Remarkable enhancement of CO2-derived poly(propylene carbonate) (PPC) against thermal decomposition was achieved by cyclization of linear PPCs. Thus, a CO2-derived linear vinyl-telechelic PPC was synthesized by CO2-propylene oxide alternating copolymerization initiated from H2O followed by an end-capping esterification with 4-pentenoic acid. Cyclic PPC was synthesized by the end-to-end intramolecular reaction of the vinyl-telechelic linear PPC by metathesis condensation. Comparison of the thermal decomposition temperature (T-d) with linear and cyclic PPCs confirms surprisingly enhanced T(d)s of cyclic PPCs. The elimination of chain ends through cyclization is indeed valuable for enhancing T-d of CO2-derived PPCs and thus turn the spotlight on the materials design utilizing CO2. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3336-3342