A novel N-hydroxy succinimide-based carbonate monomer that allows direct synthesis of polymers incorporating a reactive carbonate group in the side chain was synthesized. This new monomer was copolymerized with methyl methacrylate and poly(ethylene glycol) methylether methacrylate using free-radical polymerization to obtain organo- and water-soluble reactive copolymers. Copolymerization of the activated carbonate monomer with an azide-containing monomer and N-hydroxy succinimide-containing activated ester monomer provided orthogonally functionalizable copolymers. The pendant reactive carbonate groups of the copolymers were functionalized with amines to obtain carbamates. Polymers capable of orthogonal functionalization could be selectively functionalized as desired using subsequent 1,3-dipolar cycloaddition or amidation reactions. The novel monomer and the copolymers were characterized by H-1-NMR, C-13-NMR, and infrared spectroscopy. The efficient stepwise orthogonal functionalization of the copolymers were examined via H-1-NMR spectroscopy. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4737-4746, 2010