The organic nonlinear optical crystal of sodium sulfanilate dihydrate (SSDH) was grown by slow cooling solution growth technique using water as solvent. Single-crystal X-ray diffraction and Fourier transform infrared (FTIR) spectral analyses were used to confirm the SSDH crystals. The UV-visible and photoluminescence studies were carried out. The second-harmonic generation of SSDH was tested by Kurtz-Perry powder technique. The hardness and laser damage threshold on the (001) and (010) planes were analyzed. (c) 2007 Elsevier B.V. All rights reserved.