The synthesis, spectroscopic characterization and crystal structures of the first 1, 4-bis (4- nitrosophenyl) piperazine (BNPP)(4) bridged dinuclear complexes of rhodium (III) and iridium (III) are presented. The reaction of the μ2-halogenido-bridged dimers [(η5-C5Me5) IrX2] 2 [X= Cl (5a), Br (5b), I (5c)] and [(η5-C5Me5) RhCl2] 2 (6a) with 4 yields the dinuclear complexes [(η5-C5Me5) IrX2] 2-BNPP (7a–c) and [(η5-C5Me5) RhCl2] 2-BNPP (8a). All ...