In the present work di-sodium hydrogen phosphate single crystals have been grown from aqueous solution by slow cooling technique using a constant temperature bath (0.01degreesC). The temperature of the solution was reduced at 0.5degreesC/day and 0.15degreesC/day from 40degreesC to 35degreesC. Good quality transparent single crystals have been obtained. The solubility of the material for different temperatures has been studied. The grown crystals were studied by powder and single crystal X-ray diffraction analyses. The FTIR and UV-visible spectra of the grown crystals were recorded. The thermal behaviour of the material was studied by simultaneously recorded thermo gravimetric and differential thermal plots. (C) 2002 Elsevier Science B.V. All rights reserved.