Figure shows the extinction coefficient of NiTMP measured in toluene. It is characterized by the strong B band at 415 nm assigned to the S 0 → S 2 transition and the weaker Q band at 527 nm assigned to the S 0 → S 1 transition. The general features of the optical absorption spectrum (OAS) are well rationalized through the Gouterman four-orbital model. In D 4h symmetry, the S 0 → S 1 and S 0 → S 2 transitions are of the ligand centered (LC) type, being localized on the conjugated ring (Gouterman1959, Gouterman1961). Figure shows the theoretical OAS of NiTMP in toluene. In order to account for vibrational effects, a Wigner distribution containing 100 geometries was introduced. A final broadening of 1000 cm -1 was applied for FC and 500 cm -1 for the Wigner distribution, using a pseudo-Voigt profile. Decomposition of the two main features in terms of NTO → NTO singlet transitions indicates a dominant MLCT character with admixture of LC character rather than a simple π-π* expected from the four-orbital model. This should be ascribed to the ruffling oop distorsion.