Optically transparent organic single crystals of (E)-N'-(2,4-dimethoxybenzylidene) benzohydrazide (DMBBH) have been grown by slow evaporation technique. The detailed crystal structure of DMBBH was determined from Single crystal X-ray diffraction (SCXRD) study. The presence of active functional groups in the compound was identified by the experimental and computational Fourier transform infrared (FTIR) and NMR analyses. The UV-Vis Spectrum reveals the optical transparency of the grown crystal in the visible region. The natural bond orbital (NBO) analysis results show that the interaction between the donor π(C2-C7) and acceptor π*(C1-N8) has the highest stabilization energy (111.9 kJ/mol) and it shows the hyperconjugation within the –CONH‒ group. The first order hyperpolarizability value β₀ = 2.8501×10^-30 esu of the synthesized compound was eight times greater than that of urea (0.3728 ×10^-30 esu). The Z-scan approach revealed the nonlinear optical (NLO) behaviour and optical limiting characteristics of the molecule.

Keywords: Schiff base, Hirshfeld surface, UV-Vis, NLO, DFT.