The reaction of Ir-4(CO)(12) with Ph3GeH at 97 degreesC has yielded the new tetrairidium cluster complexes Ir-4(CO)(7)-(GePh3)(mu-GePh2)(2)[(mu3)-(eta3) GePh(C6H4)](mu-H)(2) (110) and Ir-4(CO)(8)(GePh3)(2)(mu-GePh2)(4) (11). The structure of 10 consists of a tetrahedral lr4 cluster with seven terminal CO groups, two bridging GePh2 ligands, an ortho-metallated bridging mu(3)-eta(3)-GePh(C6H4) group, a terminal GePh3 ligand, and two bridging hydrido ligands. Compound 11 consists of a planar butterfly arrangement of four iridium atoms with four bridging GePh2 and two terminal GePh3 ligands. The same reaction at 125 degreesC yielded the two new triiridium clusters Ir-3(CO)(5)(GePh3)(mu-GePh2)(3)(mu(3)-GePh)(mu-H) (12) and Ir-3(CO)(6)(GePh3)(3)(mu-GePh2)(3) (13). Compound 12 contains a triangular Ir-3 cluster with three bridging GePh2, one triply bridging GePh, and one terminal GePh3 ligand. The compound also contains a hydrido ligand that bridges one of the Ir-Ge bonds. Compound 13 contains a triangular Ir3 cluster with three bridging GePh2 and three terminal GePh3 ligands. At 151 degreesC, an additional complex, Ir4H4(CO)(4)(mu-GePh2)(4)(mu(4)-GePh)(2) (14), was isolated. Compound 14 consists of an lr4 square with four bridging GePh2, two quadruply bridging GePh groups, and four terminal hydrido ligands. Compound 12 reacts with CO at 125 degreesC to give the compound Ir-3(CO)(6)(mu-GePh2)(3)(mu(3)-GePh) (15). Compound 15 is formed via the loss of the hydrido ligand and the terminal GePh3 ligand and the addition of one carbonyl ligand to 12. All compounds were fully characterized by IR, NMR, single-crystal X-ray diffraction analysis, and elemental analysis.