This article describes the anionic copolymerization of glycidyl phenyl ether (GPE) and 1,2-dihydro-3H-naphtho[2,1-b]pyran-3-one (DHNP), a six-membered aromatic lactone bearing naphthyl moiety. The copolymerization proceeded in a 1:1 alternating manner, to afford the corresponding polyester. The ester linkage in the main chain was cleavable by reduction with lithium aluminum hydride to give the corresponding diol that inherited the structure of the alternating sequence. The copolymerization ability of DHNP permitted its addition as a comonomer to an imidazole-initiated polymerization of bisphenol A diglycidyl ether. The resulting networked polymer, of which main chain was endowed with the DHNP-derived rigid naphthalene moieties, showed a higher glass transition temperature than that obtained similarly with using 3,4-dihydrocoumarin (DHCM) as a comonomer, an analogous aromatic lactone bearing phenylene moiety instead of naphthalene moiety of DHNP. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 619-624, 2011