A new semiorganic nonlinear optical rubidium biS-DL-malato borate (RBMB) has been synthesized and single crystals were grown by slow cooling technique from aqueous solution. The grown crystals have been characterized by X-ray diffraction (single crystal XRD) to confirm the formation of the crystalline phases. FT-IR and FT-Rarnan spectroscopic analyses confirm the presence of all the functional groups in the grown crystals. TG-DTA studies reveal that the material is stable up to 230 degrees C. The UV-vis transmission spectrum shows a lower cutoff wavelength of 230 nm. The emission of SHG using Nd:YAG laser is confirmed by a modified Kurtz and Perry powder setup. (c) 2007 Published by Elsevier B.V.