International audienceN-Ethyl quinolinium derivative of PNQI has been successfully synthesized by knoevenagel condensation reaction and purified by repeated recrystallization process. The single crystal of title material was grown by slow evaporation technique using methanol as a solvent. The crystallinity of grown crystal was confirmed by powder X-ray diffraction analysis. Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopic studies were performed for the identification of functional groups present in the grown crystal. The linear optical property of the grown crystal was studied by UV-Vis-NIR spectral analysis. The photoluminescence spectrum of title crystal PNQI exhibits prominent emission peak at 567 nm. Introduction. Synthesis and design of new organic molecules with high nonlinear optical susceptibilities have been investigated due to their potential applications in telecommunications, optical computing, optical data storage, bioimaging and optical information processing [1]. In order to satisfy the day to day technological requirements, new organic nonlinear materials are mandatory which exhibits large nonlinear response compare to inorganic counterparts due to the presence of large polarisable Ο-conjugated system. Recently it has been found that the ionic organic stilbazolium family crystals are of considerable attention due to their large second and third order optical nonlinearities. In this series, quinolinium derivatives are one of the stilbazolium family and many researchers made an attempt to grow quinolinium derivative single crystals, because it possesses a large number of conjugated Ο-electrons exhibits high nonlinear optical properties. Generally, the heteroaromatic salt type electron acceptors show high electron withdrawing strength and lead to large nonlinear optical response [2]. Thus these compounds take quinolinium moiety as an electron acceptor and, their crystal phase exhibits attractive characteristics such as high macroscopic nonlinearity, advantageous spatial arrangements, high environmental stability and optical quality [3]. In the present work, we report the material synthesis, growth, spectral and optical properties of PNQI