Metalation was achieved by generating the MIC in situ through addition of 1.2 equivalents of t BuOK in a thawing solution of tetrahydrofuran (THF) at -108 °C followed by the addition of CuCl at room temperature. The reaction progress was monitored by H NMR spectroscopy to observe the loss of the triazolium aryl resonance and the product formation was confirmed by highresolution ESI-MS. However, since the Cu I Cl carbene complex appeared to decompose and showed signs of ligand exchange to give the homoleptic Cu I dicarbene complex in solution after numerous purification and crystallization attempts, we proceeded to use it directly in the next step. The final step included adding 1.1 equivalents of the donor amine (carbazole or diphenylamine) and 1.1 equivalents of t BuOK to the in situ-formed Cu I (carbene)Cl complexes, after which the final heteroleptic Cu I complexes were isolated in 75-90% yield by filtration in DCM and rinsing with diethyl ether (Et2O) work-up. Complexes Cu Mes MIC Naph Cz, Cu Mes MIC 3,5- CF3Ph Cz, and Cu Mes MIC Naph NPh2 are colorless solids, while Cu Mes MIC p-An Cz, Cu Mes MIC 3,5-CF3Ph Cz OMe , and Cu Mes MIC NPh2 are yellow, and Cu 3,5-MePh MIC Naph Cz is beige.