In salicylideneamine crystals, the dihedral angle between the salicyl plane and the adjacent phenyl (or naphthyl) plane is an indicator of photoisomerization. Most of the synthesized crystals exhibited dihedral angles ranging from 20-50° (Table ). An established empirical rule indicates that salicylideneamine crystals with dihedral angles exceeding 30° show higher propensity for photoisomerization . UV-vis absorption spectra of the crystalline powders showed absorption bands in the 300-600 nm region prior to UV irradiation, followed by enhanced absorption in the 400-600 nm range due to enol-keto photoisomerization (Supplementary Figure ). Compounds 2 and 7, having planar structures with dihedral angles of 8.48° and 21.24° respectively, displayed minimal absorption changes.