The nonlinear optical single crystals of benzimidazole were grown by slow evaporation solution growth technique. The grown crystal was confirmed by elemental analysis, single crystal and powder X-ray diffraction. The functional group of the grown crystal was found by FT-IR and laser RAMAN studies. The thermal and UV-Vis transmittance studies were performed to know the thermal and optical behavior, respectively. The NLO property of the crystal was tested by Nd:YAG laser as a source. (C) 2003 Elsevier B.V. All rights reserved.