As a final part of this study, we have computed the singlet-triplet phosphorescence energies of VCl 3 (ddpd) and the four designed complexes, which are shown alongside the experimental emission spectrum of VCl 3 (ddpd) in Figure . The emission energies were calculated at the CASPT2 level of theory at singlet geometries that were optimized starting from structures visited during the dynamics simulations (see Section S1 for details). As can be seen, the experimental emission spectrum of VCl 3 (ddpd) (A, green line) shows two peaks at 1102 and 1219 nm, while Ref. 39 assigned a third peak to the broad feature at 1256 nm following the second maximum in the experimental spectrum. Our calculations show the transitions from the lowest-excited singlet state S 1 to the lowest-energy component T 0 of the 3 T 1 ground-state term at 1028 nm (blue stick), close to the experimental peak of 1102 nm (energy difference of 0.08 eV). The transitions to the second (T 1 , orange stick) and third (T 2 , red stick) component of the 3 T 1 ground-state term follow at 1050 and 1276 nm. While the S 1 --→ T 2 transition is close to both the second and third experimentally assigned peaks, the S 1 --→ T 1 transition is closer to the first experimentally assigned peak. This suggests that the the broad feature that was assigned as a third peak in Ref. 39 may be only part of the vibrational progression of the S 1 --→ T 2 transition. The S 1 --→ T 1 transition in the experimental spectrum then corresponds to the peak at 1115 nm that is visible on the long-wavelength side of the maximum at 1102 nm.