Up to date, only a few kinds of poly (azomethine-urethane)s (PAMUs) derived from aromatic hydroxy compounds were obtained and studied with thermal degradation steps. Novel PAMUs were prepared using the hydroxy-functionalized Schiff bases derived from melamine and toluene-2,4-diisocyanate. Schiff base prepolymers were synthesized by the condensation reaction of melamine with 4-hydroxybenzaldehyde and 2hydroxy-1-naphtaldehyde. Characterization was made by UV-Vis, FTIR, NMR, and SEC techniques. Thermal characterizations of the novel PAMUs were carried out by TG-DTA and DSC techniques. Thermal decomposition steps at various temperatures were also clarified and the physical changes of the synthesized PAMUs with exposing to the thermal degradation steps were displayed. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3027-3035, 2011