The preparations os some new β-diketonate iridium(I) complexes of formula [Ir(β-diketonate)(diolefin)] and [Ir(β-diketonate-C3)(diolefin)(LL)] (β-diketone = acetyl acetone (Hacac), 1-phenyl, butane-1,3-dione (HBzac), 1,3-diphenyl,propane-1,3-dione (HBz2ac); diolefin = tetraflurobenzobarrelene (TFB), trimethyltetrafluorobenzobarrelene (Me3TFB); LL = 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) (not all possible combinations)) are reported. The neutral complexes [IrI(TFB)2] and [IrI(TFB)(phen)] were prepared by metathetical reactions from the corresponding chlorides. The oxidative addition of iodine to [Ir(acac-C3)(TFB)-(phen)] or (Ir(TFB)(phen)][ClO4] results in formation of the trans or cis isomers of the iridium(III) cation [IrI2(TFB)(phen)]+, respectively. The rans isomer has been structurally characterized by X-ray diffraction methods; the lattice constants of the monoclinic P21/n cell are a 12.6841(4), b 17.7550(7), c 13.8500(4) Å with β 108.874(2)°. The R factor was 0.058 for 3552 observed reflections. The octahedral coordination of the metal is distorted as to make an I-Ir-I angle of 160.43(4)°. We thank the Comisión Interministerial de Ciencia y Tecnología (Grant 1790/82) for financial support. Peer reviewed