and 6c show the structure in vacuum optimized with DFT. The geometries agree with the reported crystal structure. The comparison for NiTMP with Figure demonstrates that solvation does not appreciably affect the structure. In vacuum, the GS of NiTMeP exhibits an NiN of 1.930 Å and a CNNC of 38.81°, while the GS of NiTMP exhibits an NiN of 1.942 Å and a CNNC of 29.82°Figure 5d shows the theoretical absorption spectrum in vacuum for NiTMeP (black) and NiTMP (gray). For both systems, a Wigner distribution containing 100 geometries was introduced. A final broadening of 1000 cm -1 was applied. The profile of NiTMP resembles the one displayed in Figure shows the LVC energy landscape, with the singlet/triplet curves in red/blue respectively. The reaction coordinate is the same as for Figure . The LVC and TDDFT landscapes are in close agreement. The excitation energy was set to 2.97 eV (~417 nm) in order to account for the shifts between experiment and theory. The excitation bandwidth of 0.2 eV is indicated in yellow. The calculations simulate the singlet and triplet dynamics, i.e. they model the process of ISC. Figure shows the temporal evolution of the populations P S (t) and P T (t) with singlet (S) (red) and triplet (T) (blue) multiplicities over 1 ps. At t= 30 fs, P S (t) = P T (t). Fitting by single exponential rise delivers a time constant of ∼ 60 fs. The ground state recovery to S 0 P GS (t) (black) is not appreciable on this temporal window. These observations are in line with the absence of stimulated emission in the tr-OAS measurements. Vertical transition through photoexcitation creates a superposition of singlet populations with characters in decreasing weight of contribution that are in good agreement with the weight of the NTOs obtained with TD-DFT (Figure ). ISC on the femtosecond time scale converts within 50 fs part of the initial 1 MLCT population primarily into 3 MLCT/ 1,3 LC populations. Over the first ∼ 150 fs, the fractions 3 LC (25%), 3 LMCT (10%) and 3 MC (10%) fractions do not vary appreciably. Starting at ∼ 200 fs, the 3 MC population rises in tandem with a decaying 3 MLCT population and still roughly constant 3 LC, 3 LMCT populations. The delayed onset of the 3 MC populations is indicated by a star in Figure .