The oxidative polycondensation reaction conditions of 2-amino-3-hydroxypyridine (AHP) and 2-[benzilydeneimino] pyridine-3-ol (BIP) were studied by oxidants such as with air O-2, NaOCl and H2O2. Oligo-2-amino-3-hydroxypyridine (OAHP) was synthesized from the oxidative polycondensation of AHP with air O-2, NaOCl and H2O2 in an aqueous acidic and alkaline medium at 30-90 degreesC. BIP was synthesized from condensation of 2-amino-3-hydroxypyridine with benzaldehyde. Oligo-2-[benzilydeneimino] pyridine-3-ol (OBIP) was synthesized from the oxidative polycondensation of BIP with air O-2, NaOCl and H2O2 in an aqueous alkaline medium at 40-90 degreesC. About 95% BIP was converted to OBIP. The number average molecular weight, (M-n) weight average molecular weight (M,) and polydispersity index (PDI) values of OAHP and OBIP (for air O-2 Oxidant) were found to be 1433, 1912 g mol(-1), 1.33 and 2637, 5106 g mol(-1) and 1.94, respectively. At the optimum reaction conditions, the yield of OAHP was found to be 86.0% (for air O-2 oxidant), 43.0% (for H2O2 oxidant) and 85.0% (for NaOCl oxidant). At the optimum reaction conditions, the yield of OBIP was found to be 91.0% (for air O-2 oxidant), 92.0% (for H2O2 oxidant) and 95.0% (for NaOCl oxidant). The OHAP and OBIP were characterized by FT-IR, UV-Vis, H-1 and C-13-NMR elemental analysis. TG and DTA analyses were shown to be unstable of OAHP and OBIP against thermo-oxidative decomposition. According to TG analyses, the weight loss of OAHP and OBIP was found to be 97.35 and 96.60% at 520 and 685 degreesC, respectively. (C) 2004 Elsevier Ltd. All rights reserved.