Metal phosphido compounds are important synthetic intermediates in organophosphorus chemistry . Most copper phosphido compounds characterized by X-ray crystallography have oligomeric structures with a few notable exceptions . We have been studying these types of compounds as intermediates in copper catalyzed hydrophosphination . During our study, we isolated the novel bridging phosphido copper cluster, Cu4(μ-PPh2)4(P t Bu3)2 and were able to determine its molecular structure using X-ray diffraction (Figure ). We also demonstrate that 1 is an active hydrophosphination pre-catalyst.