New complexes of the type trans-[IrCl(eta(2)-COE)(NHC)(2)] (COE = cis-cyclooctene; NHC = N-heterocyclic carbene) have been prepared in one step from the reaction of ca. 4 equiv of NHC or [AgCl(NHC)] with [IrCl(eta(2)-COE)(2)](2) in benzene. These new complexes have been characterized by techniques including NMR and IR spectroscopy, X-ray crystallography, and elemental analysis. Exposing trans-[IrCl(COE)((IPrMe)-Pr-i)(2)] to CO yielded trans-[IrCl(CO)((IPrMe)-Pr-i)(2)], which is the only bis(NHC) analogue of Vaska's complex trans-[IrCl(CO)(PPh3)(2)] known to date. The synthesis of trans-[Ir(CO)((IPrMe)-Pr-i)(2)(R)] (R = MeO, PhCC, OSiPh3, O2CPh) complexes has been achieved via deprotonation reactions involving the new hydroxide species trans-[Ir(OH)(CO)((IPrMe)-Pr-i)(2)].