Additionally, XANES stands out as one of the robust techniques to identify the ligand non-innocence within transition-metal complexes. Bruin et al. has unrolled the redox non-innocence of tetra-amido macrocyclic ligand (TAML) employing experimental XANES complemented by EPR and magnetic moment measurements. The redox activity of the terpyridine ligand is well probed using XAS studies by Wieghardt et al. The redox properties of nitrogen-donor ligands in transition metal complexes is probed using N K-edge XAS and computational methods revealing significant insights into ligand behavior by Lancaster et al. Redox non-innocent ligands due to their unique electronic structure provide an opportunity to modify the reactivity and catalytic properties of transition metal complexes. They can serve as an electron reservoir, enabling the metal to accumulate electrons within the ligand. They can also act as electron donors to the metal centers, thereby refining their catalytic characteristics. Metallocorroles are the archetypal illustrations of ligands exhibiting a non-innocent nature, where the macrocyclic ring exhibits partial corrole •2-character. These compounds have garnered attention due to their promising applications in catalysis. Ghosh et al. has used XAS to explore the non-innocent behavior of metallocorroles within the families of manganese, iron, cobalt, copper and silver. Various computational methods are available to calculate the core-valence excitations such as delta self-consistent field approach (∆SCF), multiple scattering method, timedependent density functional theory (TDDFT), wavefunction-based coupled-cluster (CC) methods. Among all the methods, TDDFT is extensively employed in modeling XANES ascribed to its balance combination of accuracy and computational cost. However, TDDFT tends to underestimate the core-valence excitation energy and thus requires a rigorous calibration to acquire quantitative accuracy with experimental results. Numerous studies utilize a linear shift correction applied to the calculated pre-edge energy peaks to address this underestimation. Additionally, achieving quantitative accuracy in TDDFT simulations of XANES relies heavily on selecting appropriate functionals, basis sets, and incorporating relativistic effects. Moreover, for transition-metal complexes with near-degenerate electronic states, it misses excitations that involve higherorder configurations and fails to correctly account for the multiplet effects. Multireference wavefunction methods like multireference configuration interaction (MRCI) or multireference coupled cluster (MRCC) can effectively capture higher-order configurations with sufficient accuracy. Nonetheless, their computational cost becomes prohibitive for systems beyond a few atoms. The restricted active space self-consistent field (RASSCF), a multiconfiguration wavefunction-based method, excels as an efficient approach that offers an accurate description of the wavefunction for multireference systems. Further, to account for the dynamical correlations to obtain precise energetics, second-order perturbation theory i.e., RASPT2 is usually employed. Guo et al. have employed RASSCF/RASPT2 calculations to obtain the iron K pre-edge X-ray absorption spectra for open-shell iron complexes. In recent studies, Govind and co-workers have employed a combined DFT and wavefunction approach known as multiconfiguration pair-density functional theory (MC-PDFT) to characterize the metal K pre-edge features of aquated 3d transition metal ions. MC-PDFT demonstrated performance comparable to RASPT2 but with substantially reduced computational expense. Metallocorroles exhibit unusual electronic structures that challenge traditional singlereference DFT methods and thus, require more rigorous methods that provide a more reliable description of electron correlation. Roos et al. have studied the electronic struc- ture of chloroiron corrole using CASSCF/CASPT2 and supported the S=3/2 Fe(III) antiferromagnetically coupled with corrole radical. Phung et al. studied the electronic structure and quantified the non-innocent character of the metallocorroles of different 3d-(Mn, Fe) and 4d-metals (Ru) employing DMRG/CASPT2. Despite the significance of the multireference methods in elucidating the electronic structure of metallocorroles, a comprehensive ab initio computational study of XANES for these compounds using multireference techniques remains conspicuously absent. This study seeks to fill this gap by examining the XANES spectra of metallocorroles containing Fe, Mn, and Co shown in Figure . We conducted a comparative analysis between XANES simulations generated through DFT and multireference methods (RASSCF/RASPT2/MC-PDFT), contrasting them with available experimental XANES data. Our findings underscore the significance of employing multiconfiguration wavefunction-based methods for accurate electronic structure calculations and XANES predictions of such complexes. Intriguingly, we identified the reflection of the ligand redox non-innocence in the metal K-edge XANES pre-edge region.