Optically good quality semi-organic single crystal of sodium acid phthalate (NaAP) was successfully grown by Sankaranarayanan-Ramasamy (SR) method. Transparent, colourless < 001 > oriented unidirectional bulk single crystals of diameters 10 and 20 mm and length maximum up to 75 mm were grown by the SR method. The grown crystals were subjected to various characterization studies such as etching, birefringence, laser damage threshold, UV-vis spectrum and dielectric measurement. The value of birefringence and quality were ascertained by birefringence studies. (C) 2010 Elsevier B.V. All rights reserved.