A novel chelating copolymer resin has been synthesized through the copolymerization of o-aminophenol and melamine with formaldehyde (o-APMF) in 1:1:3 mol ratio using hydrochloric acid as a reaction medium by condensation technique. The synthesized copolymer resin was characterized by elemental analysis, FTIR, and H-1 NMR spectroscopy. On the basis of the spectral studies, the structure of the copolymer resin was proposed. The physico-chemical parameters have been evaluated for the copolymer resin. Non-aqueous conductometric titration was used to determine the average molecular weight and polydispersity of the o-APMF copolymer resin and the intrinsic viscosity was also determined. The semicrystalline nature of the synthesized copolymer was established by scanning electron microscopy (SEM). Batch equilibrium method was employed to study the selectivity and binding capacity of the copolymer resin toward certain trivalent and divalent metal ions such as Fe3+, Zn2+, Cu2+, Pb2+, Cd2+, and Hg2+ and in different electrolyte concentrations, wide pH ranges, and time intervals.