The presented full-dimensional LVC-TSH simulations both for [Fe(bmip) 2 ] 2+ and [Fe(terpy) 2 ] 2+ demonstrate the high degree of dependence of the population dynamics on the utilized electronic structure (DFT/TD-DFT) method. Importantly, B3LYP* is the only functional that reproduce all important aspects of the experimentally observed dynamics, indicating an accurate description of MLCT-MC energetics. Our assessment reveals that the exact (Hartree-Fock) exchange is the decisive factor determining the simulated dynamics. Pure GGA methods (RPBE, OPBE, BLYP) that do not contain any exact exchange tend to overstabilize MLCT states which led to failures such as lack of any dominant sub-ps 3 MC component for [Fe(bmip) 2 ] 2+ and thus hardly any observable 3 MLCT/ 3 MC branching. For [Fe(terpy) 2 ] 2+ , the 5 MC population rise obtained by GGAs is too slow and importantly, the population dynamics are rather exponential with the absence of any 5 MC-3 MC oscillations, this shows that the 3 MC states do not play an active role in the excitedstate mechanism as constructed from the GGA simulations, and the 5 MC is populated directly from the 3 MLCTs, which is in disagreement with all recent theoretical works on Fe(II) polypyridines and the time-resolved XES data. It is thus clear that a more balanced description of the MLCT-MC energetics is required in order to accurately simulate the excitedstate dynamics. A straightforward approach is to utilize hybrid exchange-correlation functionals that include a certain amount of exact exchange. However, we found that the exact exchange within the tested B3LYP, PBE0, and CAM-B3LYP functionals is too high, and that the MC states are those that are now overstabilized. Specifically, for [Fe(bmip) 2 ] 2+ , this is reflected in the rapidly decaying MLCT population, thus the experimentally observed 3 MLCT/ 3 MC branching is again not reproduced. In addition, we found based on the potentials along the principal breathing mode of [Fe(bmip) 2 ] 2+ calculated by the hybrid functionals B3LYP, PBE0, and CAM-B3LYP that the 5 MC PES is incorrectly located in a region where it could in fact play an active role in the dynamics (while it is known experimentally 30 that the 5 MC state is not involved in the photorelaxation of [Fe(bmip) 2 ] 2+ ). For [Fe(terpy) 2 ] 2+ , the excited-state description by the B3LYP and PBE0 hybrids is significantly better (as assessed by comparison to the XES experiment) but still not completely convincing as the 5 MC-3 MC oscillations present in both the experimental XES data and our B3LYP* dynamics are not observed. In contrast, B3LYP* correctly reproduces all important aspects of the dynamics both for [Fe(bmip) 2 ] 2+ and [Fe(terpy) 2 ] 2+ , signalling that an optimal balanced description of MLCT-MC energetics is achieved.