This article presents a route to a novel polyester having sequentially ordered two orthogonal reactive groups. The polyester was given by the imidazole-initiated alternating copolymerization or allyl glycidyl ether (AGE) and a bislactone 1. This copolymerization system is characterized by the following three reaction behaviors: (1) the selective participation of only one of the two lactone moieties of I to the copolymerization to give a linear polyester, and the consequent introduction of the second lactone into the side chain of the polyester, (2) the participation of the epoxy moiety in AGE to the copolymerization, and the consequent introduction of the carbon-carb on double bond into the side chain of the polyester, and (3) arrangement of the sequentially ordered two orthogonal reactive groups according to the alternating manner. The introduction of the two reactive groups to the side chain of the alternating copolymer allowed two routes of sequential chemoselective reactions: (A) The ring-opening reaction of the lactone moiety with n-propylamine and the following Pt-catalyzed hydrosilylation of the carbon-carbon double bond with dimethyl-phenylsilane and (B) the sequential reactions of the reverse order (C) 2009 Wiley Periodicals, Inc J Polym Sci Part A Polym Chem 47. 6750-6757, 2009