Investigation of the photoreduction of copper(II) to copper(I) in methanolic solutions of copper(II) chloride and copper(II) bromide indicates the halide-to-copper(II) charge-transfer (CT) responsible for the photoreduction. Quantum yields for the formation of copper(I) as a function of irradiating wavelength and copper(II) halide concentration show that [Cu(CH3OH)5Cl]+ and [Cu(CH3OH)4Cl2] have identical photoreaction efficiency, while [Cu(CH3OH)4Br2] is more photoreactive than [Cu(CH3OH)5Br]+. In the copper(II) chloride system the chloride-to-copper(II) CT band centered around 272 nm appears to be responsible for the photoreaction, while the bromide-to-copper(II) CT band centered around 245 nm effects the photoreaction in copper(II) bromide system.