This work aimed at the development of bioactive polymeric materials to be used for targeted drug delivery and tissue engineering applications. The proposed strategy was based on the design of macromolecular systems whose functionality can be easily modified. Polyesters containing side-chain end capped by primary hydroxyl groups were synthesized by polyaddition of oxetanes and carboxylic anhydrides catalyzed by quaternary onium salts. The polyaddition of bis(oxetane) with different dicarboxylic acids was also investigated. In all cases, oxetane monomers contained one hydroxyl group either free or protected by a benzyl group. The polymer yield and molecular weight were relatively high when aromatic anhydrides were used. In all other cases, low conversions or no polymerization at all were obtained. In a parallel research line, several alkanols were successfully employed to synthesize different a,alpha,beta',beta-trisubstituted-beta-lactones. These monomers were prepared in five steps starting from diethyl oxalpropionate according to established synthetic routes. Final yields depended on both preparation method and side-chain structure. By using quaternary ammonium salts as catalysts, the synthesized functional lactones underwent anionic ring opening polymerization leading to the corresponding homopolymers and copolymers in fairly good yields. The prepared polymeric materials were extensively characterized by spectroscopic techniques, size exclusion chromatography, and thermal analysis. (C) 2008 Wiley Periodicals, Inc.