A series of poly(azomethine ester) copolymers were synthesized by the solution polycondensation method with different diamines. The synthesized polymers were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), hot-stage polarized microscopy, wide-angle X-ray diffraction, and solution viscosity. All polymers showed good thermal stability. The thermotropic liquid-crystalline properties were examined by DSC and by microscopic observations. Except for one, all of the polymers showed nematic liquid-crystalline behavior. The effects of temperature on crystallinity and the substituent on solubility, thermal stability, melting temperature, and viscosity were also studied. The voluminosity and shape factor were also computed from the viscosity data. (C) 2003 Wiley Periodicals, Inc.