The dilacunary decatungstogermanate [gamma-GeW(10)O(36)](8-) (GeW(10)) and the monolacunary undecatungstogermanate [beta(2)-GeW(11)O(39)](8-) (GeW(11)) were employed as polyanions to layer-by-layer self-assembly with cationic thionine (TH) dye. The (GeW(10)/TH)(n) and (GeW(11)/TH)(n) composite films were characterized by UV-vis spectra, atomic force microscopy images (AFMs) and cyclic voltammograms (CV). Their photocatalytic activities were evaluated by photocatalytic degradation of methyl orange aqueous solution under sunlight irradiation. The results indicated that the (GeW(10)/TH)(n) and (GeW(11)/TH)(n) films exhibited the sunlight photocatalytic activities for methyl orange (MO) solution. The dye molecule TH extended the light absorption spectrum of polyoxometalates toward the visible light region. The photocatalytic mechanism of composite films was also discussed. Copyright (C) 2011 Elsevier Inc. All rights reserved.