Photochemistry resulting from excitation of a d-d transition at 575 nm between ligand-field states in the gas-phase [Cu I I (bpy)(serine-H)] + complex generated by electrospray ionization is reported. These results are discussed in terms of a reaction scheme proposed by Turecek and co-workers [C.L. Gatlin, F. Turecek, T. Vaisar, J. Mass Spectrom. 30 (1995) 1617] for collisionally activated dissociation of this complex at low center-of-mass collision energies under multiple-collision conditions. Three photofragment ions are observed, corresponding to elimination of formaldehyde, stepwise loss of formaldehyde followed by OC(OH)CHNH 2 , and transfer of a hydroxyl group to the Cu I I ion accompanied by loss of H 2 CCHNH 2 CO 2 . A fourth fragmentation channel reported by Turecek and co-workers corresponding to decarboxylation and associated dehydration is also observed at moderate center-of-mass collision energies under single-collision conditions but is absent in the laser photofragmentation difference mass spectrum resulting from excitation of [Cu I I (bpy)(serine-H)] + at 575 nm.