The novel copper iodide clusters [Cu-3(mu-I)(mu(3)-I)(2)(PH2BH2 center dot NMe3)(3)] (2) and [Cu-4(mu-I)(2)(mu(3)-I)(2)(PH2BH2 center dot NMe3)(3)] (3) were synthesized by treating CuI with the primary phosphine (H2PBH2 center dot NMe3). The novel features of both compounds, which have been characterized by X-ray crystallography, are the unsymmetrical constitution of the copper iodide core due to the influence of the monodentate phosphorus ligand. This results in copper atoms with different coordination numbers within the compound. Complex 2, the major product of the reaction, contains a distorted octahedral Cu3I3-core, in which one vertex is missing. Complex 3 was isolated as a by-product and is composed of a Cu4I4-core in a distorted octahedral coordination.