An organocatalytic approach to controlled/living ring-opening polymerizations (ROPs) of O-carboxyanhydrides (OCAs) using N-heterocyclic carbenes (NHCs) as nucleophilic catalysts has been investigated. NHCs with different structures were used in order to compare the catalytic performances in the ROP of OCA of L-lactic acid. H-1 NMR, SEC, and MALDI-TOF MS measurements of the products clearly indicated a controlled/ living manner of the polymerization. The controlled/living nature was further confirmed by kinetic and chain extension experiments. Additionally, polylol initiators were used to produce alpha, omega-dihydroxy telechelic, 3-, and 4-armed starshaped polymers. Moreover, star-shaped diblock copolymer, bearing methyl and phenyl side groups, has been successfully synthesized with OCA/NHC system. (c) 2014 Wiley Periodicals, Inc.