New redox-active hydrogel thin films with poly(hydroquinone) (PHQ) as polymeric redox couple and chitosan hydrogel as matrix are synthesized. Single-component layer-by-layer films of chitosan are first fabricated in a uniform and reproducible manner, which is proved by UV and AFM studies. The chitosan films are then treated in acidic hydroquinone (HQ) solution to introduce PHQ. In situ generation of PHQ in the films is proved by UV and FTIR spectroscopy. PHQ formation also results in an increased film roughness and thickness. We confirmed that oxygen acts as oxidant and chitosan acts as template in the polymerization of HQ. Cyclic voltammogram of the film presents two oxidation peaks at 0.21 and 0.75 V and one reduction peak at -0.15 V(vs Ag/AgCl), indicating the film, which is originally not redox-active, becomes redox-active after the introduction of PHQ. The new redox-active films may find applications in amperometric biosensors. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013