N-Ethyl quinolinium chromophore crystal 2-[2-(4-chloro-phenyl)-vinyl]-1-ethyl-quinolinium iodide (PCLQI) has been successfully grown by the slow evaporation technique. Single crystal X-ray diffraction studies revealed that the title compound crystallizes in the monoclinic crystal system with the centrosymmetric space group C2/c. The molecular formation of the grown crystal was initially identified using ¹H NMR and FTIR analysis. The linear optical studies of the title crystal were done by UV-vis-NIR studies and the thermal studies revealed the stability of the title material till its melting point at 239.7 °C. The grown crystal exhibited high third order optical nonlinearity which was determined by the Z-scan technique.