Copolymers of metanilic acid (MA) and aniline (An) deposited from different ratios of the monomers in 0.1 M H2SO4 were characterized by elemental analysis, Fourier transform IR spectroscopy, UV-visible spectroscopy, cyclic voltammetry and scanning electron microscopy. The presence of a polyaniline (PAn)-like structure in the copolymers was ascertained, although the copolymers possessed distinctly different morphologies and electrochemical behaviour in mineral acids. The copolymers were doped intramolecularly ("self-doping") by the sulfphonate functional group of MA and intermolecularly by the electrolyte anions. The total doping seemed to be limited to 50% but the extent of intramolecular doping versus intermolecular doping could be changed by adjusting the MA/An ratio in the starting mixture.