The bulk single crystals of thiourea doped ammonium penta borate were grown by slow evaporation solution growth technique using deionized water as solvent. The grown crystals were characterized by single crystal and powder Xray diffraction, FTIR spectral analysis. The range and percentage of optical transmission were ascertained by UVVis- NMR spectrum. Its second harmonic generation relative efficiency was measured by Kurtz and Perry powder technique using Nd:YAG laser. Thermal properties were investigated by TG-DTA and DSC analyses.
