(Al,Mo)-codoped ZnO powders with a constant molar ratio of Zn:Al (99:1) and various molar ratios of Mo:Al (0-0.02) were synthesized by a sol-gel process and characterized by X-ray diffraction, field emission scanning electron microscopy, and UV-vis and luminescent spectrophotometry. The experiments indicated that the powders had random orientation and a slightly larger average particle size that increased with increasing Mo proportion. The Mo doping resulted in the enhancement of transmittance in the UV-visible light range and the widening of the band gap. Optimal efficiency appeared at molar ratio of Mo:Al = 0.01, and Mo doping resulted in the formation of a new emission center and the enhancement of the emissions in range of visible light. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.