The products and the oxidative polycondensation reaction conditions of oligo-3-aminopyridine with H2O2 and NaOCl were studied. In this reaction, NaOCl was observed to be more active than H2O2 and optimum reaction conditions were determined. Oligo-3-aminopyridine (OAP) was synthesized from the oxidative polycondensation of 3-aminopyridine (AP) with NaOCl and H2O2 in an aqueous acidic medium at 25°–90°C. The products were characterized by 1H NMR, FT-IR, UV-Vis, and elemental analysis. The number-average molecular weight, weight-average molecular weight, and polydispersity index values of OAP synthesized were found to be 250, 800 g mol−1, and 3.20, respectively, using NaOCl, and 240, 840 g mol−1, and 3.50, respectively, using H2O2. The respective values of the Schiff base were 1140, 5190 g mol−1, and 4.55. At optimum reaction conditions, yields of the reaction products were 80.1% (H2O2) and 82.0% (NaOCl). About 90% AP was converted into OAP. TG analyses showed that OAP was stable towards thermo-oxidative decomposition. The weight loss of OAP was found to be 5, 50, and 92 at 125°, 617°, and 1000°C, respectively. The weight loss of oligo-aminopyridinylazomethinephenol (OAPAP) was found to be 5, 50, and 80.50 at 175°, 660°, and 1000°C, respectively. Also, a new oligomeric Schiff base was synthesized from the condensation of OAP with salicylaldehyde and their structures and properties were determined.