The electronic structures of nitrogen (N) doped HTaWO6 have been studied in the framework of density functional theory. Due to N-doping, the valence band maximum is seen to shift towards the conduction band, thus narrowing the band gap dramatically according to the calculated electronic structures. Consequently, an improved harvest of visible light is predicted and this has been confirmed experimentally by UV-visible light absorption measurements. (C) 2010 Elsevier B. V. All rights reserved.