The molybdenum(VI)dioxo-dibromo compound bearing a carboxylate substituted bipyridyl ligand was anchored covalently onto a TiO2 matrix (DG-25). It was fully characterized by IR(KBr), UV-diffuse reflectance, IR-photoacoustic (FT-IR/PAS) and solid state C-13 NMR spectroscopies. Its reactivity as an O-atom transfer agent was tested under visible light irradiation on ethylbenzene and tetraline, stoichiometrically under N-2 and catalytically Under O-2 and then compared with the analogous homogeneous complex bearing a carbomethoxy substituted bipyridine. An important synergic effect was observed, attributed to the photogenerated electron flux, via TiO2, onto the coordination sphere of molybdenum. The anchored system, furthermore, prevented any deactivation of the reactive center, as it is observed in the homogeneous medium, through the formation of a mu-oxo species. (C) 2008 Elsevier B.V. All rights reserved.