To summarize, BSE@GW theory does yield results for MC transitions that are either of similar or of improved quality when compared to common TDDFT calculations. The situation was simple for the two closed-shell systems where both TDDFT and BSE@GW gave acceptable results. The Ni(III) system, however, demonstrates the advantage of the BSE@GW framework, which provides a more balanced description of excited states with partial CT character. This advantage comes at an additional computational cost in the form of the calculation of the GW quasiparticle energies. In the case of pronounced multiconfigurational character (Co(II)) both TDDFT and BSE@GW fail. Previous research has investigated the effect of NHC units on the absorption spectra of Fe(II) complexes using TDDFT and range-separated functionals to describe CT transitions. It was found that the inclusion of NHC units can destabilize the lowest triplet MC states, leading to a longer MLCT lifetime upon excitation. Based on these observations regarding strongly mixed states and research highlighting the BSE@GW framework's effectiveness in describing CT states, we aim to re-investigate these systems using the BSE@GW approach. From Ref. 60, we selected the three systems shown in Fig. . We also maintain the previous notation, i.e. 5 [Fe(terpy) 2 ] 2+ (reference for the effect of NHS ligands), 4