The effect of the organic hole scavenger on copper photodeposition at TiO2 was investigated as a function of organic concentration and pH. Copper photodeposition was observed in solutions containing sodium formate, sodium oxalate, citric acid, disodium-EDTA, methanol, ethanol, n-propanol, 2-propanol, n-butanol, propiolic acid, isobutyric acid, chloroacetic acid, or DL-lysine monochloride. No copper photodeposition was observed in solutions containing sodium acetate, sodium propionate, sodium butyrate, tert-butyl alcohol, acetone, salicylic acid, ethyl acetate, dichloroacetic acid, trichloroacetic acid, malonic acid, succinic acid, methyl propionate, acrylic acid, methacrylic acid, crotonic acid, phenol, vinyl acetate, chloroform, trichloroethylene, dichloroethane, triethylamine, ethylenediamine, or methylhydroquinone. For solutions containing organics in which copper photodeposition did not occur, addition of small amounts of sodium formate resulted in photodeposition of the copper. The rates of copper photodeposition and subsequent oxidation of the photoreduced copper with oxygen were dependent on the organic hole scavenger. Powder X-ray diffraction was used in an attempt to determine the reduced copper species formed on the TiO2.