The sonochemical synthesis, structural analysis, theoretical calculations, and the nonlinear optical (NLO) discovery of benzylidenehydrazono thiazolidin-4-one derivative 8, that is, (Z)-ethyl-2-((Z)-2-((E)-(4-chlorobenzylidene)hydrazono)-4-oxo-3-phenylthiazolidin-5-ylidene) acetate (C20H16ClN3O3S), are detailed. The 1H and 13C NMR data, melting point (m.p), infrared spectrum (IR), mass spectrum, and UV-visible spectrum measurements are used to confirm the authenticity of the synthesized derivative 8. The geometrical structural optimizations and theoretical properties of the synthesized compound are performed using density functional theory (DFT). The NLO properties of the synthesized derivative 8 are studied under continuous wave (cw) 473-nm laser beam via conducting the closed (C)- and open (O)-aperture (A) Z-scan techniques where the nonlinear refractive index (NLRI) and the nonlinear absorption coefficient (NLAC) are obtained, viz. 1.79 x 10-7 cm2/W and 2.72 x 10-3 cm/W, respectively, and an optical limiting (OLg) threshold of 13 mW is obtained.
