A new class of optically active poly(amideimide-urethane)s (PAIUs) was synthesized via a two-step diisocyanate route under microwave irradiation. In these reactions, 4,4'-methylene-bis(4-phenylisocyanate) was reacted with bis(p-amido benzoic acid)-N-trimellitylimidO-L-leucine and poly(ethylene glycol diol)s (PEGs), such as PEG-400, PEG-600, PEG-1000, and PEG-2000, to furnish a series of new PAIUs. The effects of different reaction conditions, such as the method of preparation (polyol or acid chain extension), the prepolymerization step (NCO-terminated oligoamide or NCO-terminated polyether polyol), the irradiation time and power, the reaction solvent, the soft-segment length, and the presence or absence of reaction catalysts (e.g., triethylamine, pyridine, and dibutyltin dilaurate), on the properties of the copolymers, including the solubility, viscosity, and thermal behavior, were investigated. The resulting multiblock copolymers had inherent viscosities of 0.15-0.53 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide-type solvents. (c) 2005 Wiley Periodicals, Inc.