The electroactivity of chemically synthesized polyaniline and its copolymer with metanilic acid has been investigated in a wide pH range. It was found that the external doping of PAn with camphorsulfonic acid extends the electroactivity in neutral and alkaline media. Additional ring substitution with sulfo-groups does not further extend the electroactivity, but improves the stability upon cycling in neutral and alkaline media. (C) 2003 Elsevier Science B.V. All rights reserved.