Nitric oxide (NO, nitrogen monoxide) has an established repertoire in mammalian biology with well-known roles in the cardiovascular, neurological, and immune response systems. Photochemical reactions of metal nitrosyl complexes are relevant as a strategy for the delivery of therapeutic NO to specific tissue sites. In this proposal, we focus on FeNO-corroles due to their potential in photodissociation dynamics that may help in the design of photo-NORMs (NO-releasing molecules) used in the development of strategies for the therapeutic delivery of NO to specific tissue sites. The axial lability of the NO bond is determined by the Fe orbital occupation, which in turn is strongly influenced by the (non-)innocence character of the corrole ligand. FeNO-corroles have long been thought of as classic {FeNO}6 complexes, while recent studies provided evidence, including infrared spectroscopy and broken-symmetry (BS) Density functional theory (DFT) calculations, that indicate a non-innocent, {FeNO}7-(corrole•2–), formulation for these complexes. However, Fe L-edge soft X-ray absorption spectroscopy (XAS) measurements together with Fe Kβ X-ray emission spectroscopy (XES) clearly show that the Fe center is in a low spin configuration with either Fe(II) S=0 or Fe(III) S=1/2 with a good amount of π back-bonding. Estimating the exact amount of corrole non-innocence character is challenging since it depends on the theoretical approach. The exact nature of the ligand innocence character is thus not fully settled. Even though it has to be small, it can have critical implications for the function of photo-NORM molecules. To fully understand or correlated the orbital interactions between the metal and corrole ligand, experimental data (different types of X-ray spectroscopies) of FeNO-corrole molecules with meso-tris(para-X-phenyl)corrole ligands (Fe[Y8TpXPC](NO)) with X= OMe, H, and CF3, Y = H, or Br the corresponding β-octabromo complexes will be available from our collaborator, these data will be interpreted through quantum chemistry simulations together with our own developed analysis tools.