The reactivity of olefin containing complexes of the d(8) metals Ru(0) and Rh(I) toward GaCp* and AlCp* is presented. [Ru(eta(4)-butadiene)(PPh(3))(3)] reacts with GaCp* to give the substitution product [Ru(eta(4)-butadiene)(PPh(3))(2)(GaCp*)] (1), which proved to be stable in the presence of GaCp* even under hydrogenolytic conditions. In contrast, the bis-styrene complex [Ru(PPh(3))(2)(styrene)(2)] undergoes full substitution of the olefin ligands to give [Ru(PPh(3))(2)(GaCp*)(3)] (2), whereas reaction of [Ru(eta(2),eta(2)-COD)(eta(6)-COT)] (COD = 1,5-cyclooctadiene, C(8)H(12), COT = 1,3,5-cyclooctatriene, C(8)H(10)) and GaCp* leads to [Ru(eta(2),eta(2)-COD)(GaCp*)(3)] (3) under mild hydrogenolytic conditions. Analogously, the Rh(I) compounds [{Rh(eta(2),eta(2)-NBD)(PCy(3))(2)}{BAr(F)}] (NBD = norbornadiene) and [{Rh(eta(2),eta(2)-COD)(2)}{BAr(F)}] ({BAr(F)}= B{[C(6)H(3)(CF(3))(2)](4)) yield the complexes [{Rh(eta(2),eta(2)-NBD)(PCy(3))(GaCp*)(2)}{BAr(F)}] (4), [{Rh(eta(2),eta(2)-COD)(GaCp*)(3)}{BAr(F)}] (5), and [{Rh(eta(2),eta(2)-COD)(AlCp*)(3)}{BAr(F)]}] (6) upon reaction with the appropriate ECp* ligand (E = Al, Ga). All new complexes have been characterized by means of (1)H and (13)C NMR spectroscopy and elemental analysis, as well as X-ray single crystal structure analysis in the case of 1-5.