Pentamethylcyclopentadienyl iridium dichloride dimer is an organometallic compound with the formula [(C5(CH3)5IrCl2)]2, commonly abbreviated [Cp*IrCl2]2 This bright orange air-stable diamagnetic solid is a reagent in organometallic chemistry.

The terminal and bridging Ir-Cl bonds have the lengths 2.39 and 2.45 Å, respectively.

[2] More conveniently, the compound is prepared by the reaction of hydrated iridium trichloride and pentamethylcyclopentadiene in hot methanol, from which the product precipitates[1] The Ir-μ-Cl bonds are labile and can be cleaved to give a variety of adducts of the general formula Cp*IrCl2L.

The chloride ligands can also be replaced by other anions such as carboxylates, nitrite, and azide.

[Cp*IrCl2]2 is a precursor to catalysts for the asymmetric transfer hydrogenation of ketones.