Multicolor expressible ECD materials consisted of polyaniline and anionic quinone

An anionic quinone, 1-amino-4-bromoanthraquinone-2-sulfonic acid, in 0.1 M (1 M = 1 mol dm3) H2SO4 looked bright red in the oxidized state and colorless in the reduced state. Polyaniline film on an ITO electrode not only electrocatalyzed the redox reaction of the quinone markedly but also incorporated the quinone inside. The polyaniline film incorporated the quinone showed colorless-green-bluish purple color change by applied potentials.