Fully sulfonated polyaniline was produced during the electrochemical polymerization of orthanilic, metanilic, and sulfanilic acids in dimethylsulfoxicle (DMSO). The dry conductivity values of the polymers obtained from the above three isomers of aminobenzene sulfonic acids were found to be 0.052, 0.087, and 0.009 S/cm, respectively. Furthermore, partially sulfonated copolymers of these aniline sulfonic acids and aniline were also synthesized electrochemically in DMSO. The dry conductivity values of the copolymers obtained from these three acids were found to be 0.094, 0.26, and 0.033 S/cm, respectively. The polymers and copolymers are soluble in water, DMSO, and N-methyl-2-pyrrolidone. The structure and properties of these polymers and copolymers were elucidated using cyclic voltammetry, scanning electron microscopy, Fourier transform infrared, elemental analysis, and ultra violet-visible absorption spectroscopy. (C) 2003 Wiley Periodicals, Inc.