This poster presents a computational density functional theory (DFT) study on the nonlinear optical (NLO) and electronic properties of (N1E, N4E)-N1-(2-nitrobenzylidene)-N4-(3-nitrobenzylidene)benzene-1,4-diamine (NNBD). Using B3LYP and ωB97XD functionals with the 6-311++G(d,p) basis set, we analyzed optimized geometries, frontier molecular orbital energies, solvent effects, UV-Vis absorption, and hyperpolarizability parameters (α, β, γ). Results show that NNBD possesses a low HOMO–LUMO gap (2.971 eV in acetonitrile), a moderately high light-harvesting efficiency (56–65%), and strong hyperpolarizability values significantly higher than those of urea (Standard). These findings indicate NNBD’s potential as an organic semiconductor, nonlinear optical material, and photosensitizer for solar cell applications.

Keywords: Nonlinear optics, density functional theory, hyperpolarizability, Schiff base, semiconductor, photosensitizer, organic electronics.