ATCC was synthesized in deionized water by solvent evaporation method. Its (powder) SHG efficiency is higher than that of urea. Single crystals of the co-ordination complex nonlinear optical crystal tri-allylthiourea cadmium chloride (ATCC) with dimensions of 8 mm x 8 mm x 4 mm were grown from aqueous solution by slow evaporation as well as by slow cooling methods. The grown crystals were characterized with single crystal X-ray diffraction, Fourier transform infrared and Raman spectroscopy, UV-vis transmittance and absorbance studies, microhardness, thermal and etching studies to understand the physico-chemical properties of the as grown single crystal. Nonlinear optical study was also carried out to test the SHG property. (c) 2007 Elsevier B.V. All rights reserved.