In order to gain a better understanding of the emission mechanism, TD-DFT studies were carried out on all the complexes, except Cu Mes MIC 3,5-CF3Ph Cz OMe , which did not allow proper convergence of the vibronic calculations. First, a ground-state optimization was carried out with B97X-D exchange-correlation functional combined with the 6-311G(d,p) basis set for light elements and LanL2Tz pseudopotential and basis set for Cu. These optimizations were started from the available X-Ray structures. Next the lowest energy singlet (S1) and triplet (T1) state structures were optimized using the corresponding TD-DFT level, applying the Tamm-Dancoff (TDA) approximation for the triplet state as this approach is known to be more suited for the triplets. All transition properties were determined with a larger basis set, namely 6-311+G(2d,p) [LANL2TZ+f for Cu]. Gratifyingly, the structural parameters of the optimized ground-state structures closely matched those observed in the X-ray crystal structures, which validates the suitability of the selected computational methodology.