Since Cu Mes MIC 3,5-CF3Ph Cz OMe has a more electron-rich 3,6-dimethoxycarbazolide ligand than Cu Mes MIC 3,5-CF3Ph Cz, the HOMO of the former is higher in energy, which is reflected in a cathodically shifted Eox (Figure and 3c, respectively). Likewise, when comparing the more electron-rich diphenylamide ligand of Cu Mes MIC 3,5-CF3Ph NPh2 (Figure ) relative to the less electron-donating carbazolide in Cu Mes MIC 3,5-CF3Ph Cz (Figure ), the Eox of the former was less positive, in line with an upshifted HOMO. In addition, we examined the effects of a 3,5-dimethylphenyl substituent in Cu 3,5-MePh MIC Naph Cz that can conjugate with the triazole ring, instead of the mesityl motif that has ortho methyl groups in Mes MIC Naph CuCz that hinder delocalization with the carbene (Figure and Table ). Accordingly, Cu 3,5-MePh MIC Naph Cz (Figure ) displayed an Eox that is slightly cathodically shifted compared to Cu Mes MIC Naph Cz (Figure ), which is consistent with our hypothesis that the 3,5-dimethylphenyl group is more electron-donating to the triazole ring and the higher conjugation owing to the coplanarity leads to a more easily oxidized Cu complex, although the effect is less dramatic than that from the amide donor. Overall, the electrochemical data indicate that the oxidation potential is fairly sensitive to the amide, with the following sequence in the electron-donating abilities: 3,6-dimethoxycarbazolide > diphenylamide > carbazolide. In contrast, the effects of the electronic structure of the carbene ligand are subtler; the 1-aryl groups are completely orthogonal to the triazole ring and have little effect on the redox potentials, while the 3-aryl groups have smaller dihedral angles with the carbene ring (Figure ) and exert slightly stronger, albeit still weak influence on the electronic structures.