A series of organorhodium and -iridium complexes M(R)(CO)(PPh3)2 (M = Rh: R = C6H5, 2-MeC6H4, 4-MeC6H4, 2,4,6-Me3C6H2, CH3, CH2SiMe3, CH2CMe3; M = Ir: R = CH3, CH2Ph, CH2SiMe3, CH2CMe3) has been prepared from MCl(CO)(PPh3)2 and the corresponding organolithium or Grignard reagents. Of these compounds, the mesitylrhodium complex Rh(2,4,6-Me3C6H2)(CO)(PPh3)2 as well as the iridium and rhodium alkyls with Me3SiCH2 and Me3CCH2 ligands show cis,trans-isomerism which is demonstrated on the basis of infrared and NMR spectroscopic evidence.