In order to systematically increase from the minimal active space, the remaining 3d orbitals, the correlating 4d orbitals, and a metal-ligand σ-bonding orbital are added, resulting in a (14e,15o) active space. In previously published work, 37 C 2 symmetry was imposed for the saddled geometry; therefore, the two corrole Gouterman π orbitals with b symmetry were kept in the active space, allowing them to mix with the d x 2 -y 2 orbital, while the orbitals with a symmetry were taken as inactive or virtual, reducing the computation to a (12e,13o) active space. Since this study does not impose symmetry, such a reduction in active space was not feasible. Upon performing computations with the larger (14e,15o) space, differences less than 2 kcal/mol in the vertical excitation energies were obtained compared to the minimal active space for both complexes (Table ). However, the CASSCF wavefunctions for the S 0 states were impacted. The same three dominant electronic configurations are involved, but the weights of their contributions change significantly. Specifically, the configuration with the largest contribution changes. In the unsubstituted corrole, the largest contribution with this active space is from the HF determinant with a contribution of 52.0%, followed by 27.0% from (π a 2 ) 2 (π b 1 ) 1 (d x 2 -y 2 ) 1 , and 13.0% from (π a 2 ) 2 (π b 1 ) 0 (d x 2 -y 2 ) 2 . Once again, the values change similarly for the functionalized corrole becoming 54.0%, 25.7%, and 12.7%, respectively. Given that there is a larger contribution from the closed shell HF determinant than in the minimal active space, this suggests that the truncated space overestimates ligand non-innocence, potentially due to excluding the metal-ligand σ-bonding orbital. For the saddled geometry Pierloot et al. obtained a larger contribution from the HF configuration (74%). They used the (12e, 13o) active space on a C 2 symmetrized molecule. On the bare copper corrole, they also report a configuration involving a double excitation from the copper d x 2 -y 2 -corrole π b 1 bonding orbital to its corresponding antibonding orbital that contributes 23% to the total wavefunction while the same configuration is reduced to 13.0% with the (14e,15o) active space.