Photolysis of [Tp*Rh(eta(4)-1,5-COD)] (1) under bar (Tp* = hydridotris(3,5-dimethylpyrazolyl)borate, 1,5-COD = cyclooctadiene) in benzene at 400 nm gives a quantitative yield of the new compound [Tp*Rh(eta(4)-1,3-COD)] (2) under bar. Selected photolysis of (2) under bar at 336 nm can be used to produce (a) hydrido-phenyl-phosphite [Tp*Rh(H)(C6H5)P(OMe)(3)], (b) hydrido-carbonyl [Tp*Rh(H)(2)(CO)], (c) chelate [Tp*Rh(C6H5)((CH2CH2COOBu)-Bu-t] when the photoreactions were made in the presence of P(OMe)(3), CH3OH and Bu-t-acrylate, respectively. These results are interpreted in terms of oxidative addition reactions by the reactive intermediates photogenerated in the Rh system (2) under bar. (C) 2003 Elsevier Science B.V All rights reserved.