Single crystals of a new nonlinear optical material, L-alaninium maleate, were successfully grown by slow evaporation of the aqueous solution at room temperature (30degreesC). The grown crystals were characterized by single crystal X-ray diffraction to determine the cell parameters and by FT-NMR and FT-IR techniques to confirm the formation of the expected compound. Thermogravimetric and differential thermal analyses reveal good thermal stability of the material. UV-Vis-NIR transmittance and powder SHG studies also have been carried out. (C) 2003 Elsevier B.V. All rights reserved.