Poly(S-amino-1,4-naphthoquinone), PANQ, films are electroactive in both aqueous and organic solutions. The redox process of both the film and the quinone groups has been studied by MIRFTIRS and Probe Beam Deflection. The quinone system is very stable in acetonitrile and in aqueous solutions up to pH 11, Therefore, its redox properties suggest potential applications in diverse areas.