Synthesis, spectral, optical properties and theoretical calculations on schiff bases ligands containing o-tolidine

•The synthesis of schiff bases were obtained by condensation of o-tolidine with salicylaldehyde and cinnamaldehyde.•The obtained ligands were characterized by UV, 1H and NMR.•Third-order NLO properties were measured using the third harmonic generation technique on thin films at 1064 nm.•Frontier molecular orbital analysis is provided.

This paper explores the synthesis, structure characterization and optical properties of two new schiff bases. These compounds were obtained by condensation of o-tolidine with salicylaldehyde and cinnamaldehyde. The obtained ligands were characterized by UV, 1H and NMR. Their third-order NLO properties were measured using the third harmonic generation technique on thin films at 1064 nm. The electric dipole moment (μ), the polarizability (α) and the first hyperpolarizability (β) were calculated using the density functional B3LYP method with the lanl2dz basis set. For the results, the title compound shows nonzero β value revealing second order NLO behaviour.