The code for calculating the HER overpotential is given below The structural configuration (Figure a-f) (Table ) of the photocatalytic material derived from phenalene, characterized by an N-Pt-N bond length of 2.038 Å and 2.042 Å, along with a bond angle of 93°, highlights a nearly planar coordination geometry around the platinum center. This precise geometric arrangement facilitates effective π-backbonding between the platinum and nitrogen atoms, which stabilizes the complex and optimizes charge delocalization across the conjugated phenalene framework. Such a structure is highly conducive to enhancing the material's optical properties, particularly by lowering the bandgap and promoting efficient charge transfer transitions. This structural rigidity and symmetry play a crucial role in modulating the light absorption spectrum, favoring broader and more intense absorption in the visible range, thereby improving the photocatalytic efficiency under UV irradiation .