Reactions of the isomers Cp*Ir(eta(4)-2,5-Me(2)T) (1) and Cp*Ir(C,S-2,5-Me(2)T) (2), where 2,5-Me(2)T is 2,5-dimethylthiophene, with Ru-3(CO)(12), Re-2(CO)(10), Mn-2(CO)(10), and [(eta(6)-C6H6)RuCl2](2) yield a remarkable diversity of products. With Ru-3(CO)(12), both 1 and 2 give the CO-substituted product Cp*Ir(eta(4)-2,5-Me(2)T . Ru-3(CO)(11)) (4), in which the 2,5-Me(2)T group is eta(4)-coordinated to the Ir and S-coordinated to a Ru in the plane of the triangular Ru-3(CO)11 cluster. With Re-2(CO)(10), 1 reacts to give the CO-substituted product Cp*Ir(eta(4)-2,5-Me(2)T .-Re2CO)(9)) (6), in which 1 is S-coordinated in an equatorial position of the metal-metal dimer Re-2(CO)(9). However, another product of this reaction is Cp*Ir(eta(4)-SC(3)H(2)MeC(=O)Me)[Re-2(CO)(9)] (7), in which the 2,5-Me(2)T ligand has been converted to a ring-opened acyl-thiolate unit that is S-coordinated to Re-2(CO)9. Compound 7 is the major product of the reaction of 2 with Re-2(CO)(10). The reaction of 2 with Mn-2(CO)(10) gives Cp*Ir(eta(4)-SC(3)H(2)MeC(=O)Me)[Mn-2(CO)(9)] (9), the Mn analog of 7. The reaction of [(eta(6)-C6H6)RuCl2](2) with 1 gives the product Cp*Ir(eta(4)-2,5-Me(2)T . Ru(eta(6)-C6H6)Cl-2) (10), which illustrates again the strong S-donor ability of the Cp*Ir(eta(4)-2,5-Me(2)T) (1) group. Structures of 4, 6, and 7 were established by X-ray diffraction studies.