In addition to the RASPT2 calculations discussed in the prior section, single-point calculations with other CAS or RAS spaces were performed for the two lowest singlet and triplet Table : Energy differences (kcal/mol) for the triphenyl copper corrole in the S 0 and T 0 states on their optimized geometries. The values are reported at the level of theory for which geometry optimization was performed, with the exception of the RASPT2 number where the values are corrected using electronic energy contributions with RASPT2(28e,2h,2e; 12o,5o,8o)/ANO-RCC but thermal corrections are computed with XMS-CASPT2 with (4e,5o). states on the XMS-CASPT2 S 0 and T 0 minimum energy structures. The relative energies and wavefunctions obtained with the (4e,5o) active space reported in this section are consistent with those used in the optimizations, although the software package employed and basis set choice has changed (Table ). The vertical excitation energies on the S 0 optimized structures are reported in Tables (Note that vertical excitations on the T 0 optimized structures are reported in Table , while the corresponding wavefunctions are included in Tables S9. For both corroles in the saddled S 0 optimized geometry, the T 0 state is lower in energy than the S 1 state (Table ).