Copolymerization of diphenylamine (DPA) with N-methyl aniline (NMA) was carried out in aqueous sulfuric acid medium by pulse potentiostatic method (PPSM). The copolymer film was grown on the surface of the working (platinum) electrode for various experimental conditions and the charge associated with film deposition was followed by cyclic voltammetry. The charge values were correlated to the amount of copolymer deposition (growth) and amount of copolymer deposited per unit time of electropolymerization (growth rate). The kinetics of the electrochemical copolymerization was followed by deducing the growth and growth rate equations in terms of charge associated with the film deposition and the conditions of electropolymerization. The deduced growth and growth rate functions indicate the dependences of concentration of DPA and NMA. The copolymer was also synthesized through oxidative polymerization and characterized by conductivity measurement, Fourier transform infra-red spectroscopy, nuclear magnetic resonance spectroscopy, ultra violet-visible spectroscopic techniques and thermogravimetric analysis. (C) 2003 Elsevier B.V. All rights reserved.