The (E)-5-(diethylamino)-2-((3,5-dinitrophenylimino)methyl)phenol was deliberated by ultraviolet-visible (UV-Vis) and Fourier transform infrared (FT-IR) spectroscopy techniques. Hirshfeld surface analysis was performed to analyze the contribution of intermolecular contacts in crystal structure of the studied Schiff base ligand. The plots of the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the electrostatic potential (ESP) were used to research the nucleophilic and electrophilic attack sites for the Schiff base ligand. According to the ESP analysis, the electrophilic reactivity was mainly found in nitro and hydroxy groups attached to phenyl rings, while the nucleophilic attack was more concentrated on hydrogen atoms. Major contributions from molecular orbitals to the electronic transitions computed according to the time-dependent DFT (TD-DFT) method were investigated using chloroform as a solvent. The topological parameters; electron density, Laplacian of electron density, kinetic energy, electron potential energy density, total electron energy density, ellipticity, and hydrogen bond energy at the bond critical points have been evaluated.