Transition metal oxides at their highest oxidation states usually show semiconducting properties. The most notable example is titanium dioxide, whereas other oxides and oxide binary phases are also wide band gap semiconductors. These materials are usually studied from the point of view of the solid state chemistry or catalysis, but their semiconducting properties upon interaction with photosensitizers are not well recognized with the notable exception of titanium dioxide. Application of these semiconductors as materials for switching devices is also not well recognized. This review paper describes the electronic structure and reactivity of several transition metal oxides towards 2,3-dihydroxyacenes. Furthermore, a simple quantum-mechanical model for the description of such systems is provided. It is demonstrated that not only titanium dioxide, but also other d 0 transition metal oxides can be photosensitized with catechol-derived ligands and that the properties of such systems are strongly affected by the nature of the ligand.