In the present work, a new organic second order NLO material: L-isoleucinium p-toluenesulfonate monohydrate (LIPT) is synthesized and reported for the first time. The LIPT is crystallized in a non-centrosymmetric monoclinic space group P21. Structural and hydrogen bond nature of the compound is analyzed using single crystal X-ray diffraction studies. The crystal exhibits very good optical properties such as wide optical transparency in the region of 210 nm to 1100 nm and the ultraviolet wavelength emission (λ = 283 nm). The second harmonic generation efficiency is found to be 1.7 times the standard KDP. Good thermal, mechanical properties and low dielectric constant at high frequency range show that the material may be a potential candidate for optoelectronic applications.