The ordering of the S 1 and T 1 states depends on the active space choice and whether or not dynamical correlation is included by means of perturbation theory. Nevertheless, if one compares the CASPT2 relative energies for the minimal (4e,5o) active space with those obtained by RASPT2, the results are consistent, supporting the choice to optimize only with the minimal active space. With RASPT2, the T 0 state is 9.7 kcal/mol higher than the S 0 state in the unfunctionalized corrole, but the separation is slightly larger in the triphenyl corrole at 12.1 kcal/mol. Additionally, the S 1 and T 1 states are slightly higher in energy in the functionalized corrole. The energy splitting between S 1 and T 1 ranges from 0.1 to 1.0 kcal/mol in CASPT2(4e,5o) and RASPT2 in both copper corroles on S 0 geometries, whereas this difference in the CASPT2(14e,15o) calculations is slightly higher at 1.7 kcal/mol and 1.6 kcal/mol for the unsubstituted and triphenyl copper corroles, respectively.