Synthesis, growth and spectral studies of S-benzyl isothiouronium nitrate by density functional methods

► S-benzyl isothiouronium nitrate, a new NLO crystal was grown by slow evaporation method. ► STBN crystallized in monoclinic system with space group P21/C. ► SBTN exhibits second order NLO susceptibility, due to intermolecular charge transfer. ► UV-Vis spectral study reveals that SBTN crystals are transparent in the wavelength region 200-1000 nm. ► The TGA study supports the crystal is thermally stable up to 196 °C. SHG efficiency of SBTN is 0.45 times of urea.