Two zone growth technique (TZGT) is reported for the growth of 4'-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST) crystals, being one of the best organic materials for second-order nonlinear optics. The growth rates are estimated with respect to the temperature difference (AT) between the hot zone and cold zone. The grown crystals are morphologically interpreted. The crystal quality is examined from the XRD double crystal rocking curve. The microhardness number has been estimated for the DAST crystals grown at the different Delta Ts. A good optical transmission is found in the cleaved plate of grown DAST crystal. The formation of microcrystals is observed on the (0 0 F) face. (c) 2005 Elsevier B.V. All rights reserved.