Abstract Photoreduction yields of Eu 3+ to Eu 2+ in aqueous and alcoholic solutions were determined. The highest quantum yields were found to be 0.97 ± 0.16 for EuCl 3 in methanol under 308 nm excitation and 0.94 ± 0.17 in 2-propanol under 248 nm excitation. The lowest quantum yield was 0.12 ± 0.02 for Eu(ClO 4) 3 in aqueous solution under 193 nm excitation. The high photoreduction yields for EuCl 3 indicate that Cl' reacts efficiently with neighbouring alcohols. The yield was found to depend on the excitation wavelength for EuCl 3 in methanol solution.