In the case of Co(II), all the obtained spectra consist of almost pure MC transitions but show a strong mismatch with the experiment. This is the case not only for the DFT equilibrium geometries but also for the MP2 one. TDDFT is a theory that is based on only a single determinant. Since BSE@GW is built around a DFT input, it also becomes a single determinant theory, for which one can assume that it is incapable of describing effects that require more than one determinant (static correlation). We assume that the lack of both levels of theory to accurately describe these systems originates from this fact. A qualitative observation of the electronic configuration suggests that this system may be multiconfigurational, as there are three possible configurations for the t 2g orbitals. Furthermore, research on other Co(II) systems with different ligand environments has already shown that multiconfigurational methods are required to accurately describe these systems. It was especially shown that DFT is not capable of describing effects such as Jahn Teller distortions in the case of this particular system. Thus this system demonstrates a limitation of the BSE@GW theory.