4-methyl N-(4-chlorobenzylidene)aniline (4CBT) single crystal with dimension of 10 × 7 × 2 mm3 has been grown by the slow evaporation solution growth method. 4CBT crystal belonging to the monoclinic crystal system with space group of P21/c was studied by single-crystal X-ray diffraction. Fourier transform infrared analysis shows the existence of functional groups in 4CBT crystal. The existence of different protons position is confirmed using 1HNMR analysis. The optical nature of 4CBT is illustrated with help of cut-off wavelength and the transparency of the titled compound. The thermal stability of the grown crystal was analysed by thermogravimetric technique. Dielectric studies were also studied with respect to temperature and frequency. The energy values of highest occupied molecular orbital and lowest unoccupied molecular orbital have been measured by frontier molecular analysis. Third-order nonlinear optical properties of 4-methyl N-(4-chlorobenzylidene) aniline crystal were measured by Z-scan technique and the measured values of the nonlinear index of refraction and absorption coefficient shows the suitability of grown crystal for photonic applications. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.