The dimeric [{(η5-C5Me5)M(μ-Cl)Cl}2] complexes (η5-C5Me5 =pentamethylcyclopentadienyl; M=Rh and Ir) react with several arylazoimidazole (RaaiR′) ligands, viz., 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et), to afford complexes of the type [(η5-C5Me5)MCl(RaaiR′)]+ where M=Rh or Ir; R, R′=H (1, 7), R=H, R′=CH3 (2, 8), R=H, R′=C2H5 (3, 9), R=CH3, R′=H (4, 10), R, R′=CH3 (5, 11), R=CH3, R′=C2H5 (6, 12), respectively. These complexes have been characterized by FT IR, FT NMR spectroscopy as well as by analytical data. The molecular structure of the hexafluorophosphate salt of the complex [(η5-C5Me5)RhCl(Me–C6H4–NN–C3H3N2)]+ 4[PF6] has been established by single crystal X-ray diffraction study.