A new organic nonlinear optical crystal, L-alanine DL-malic acid (LADLMA), has been grown from aqueous solution by the slow cooling technique. L-alanine and DL-MaliC acid were used in the ratio 2:1 for synthesis. Crystals of size 24 x 13 x 8 mm(3) have been obtained in 26 days. Characterizations were carried out to study the structural, optical and mechanical properties of the grown crystals. Single crystal X-ray diffraction analysis shows that they belong to the orthorhombic system. To study the crystalline perfection of the grown crystals, high-resolution X-ray diffraction (HR-XRD) study was carried out. The vibrational frequencies of various functional groups have been derived from FTIR spectrum. Thermal behaviour of the crystal was investigated by TG-DTA analyses. Transmission spectrum has been recorded in the solution state and the cut-off frequency has been determined. Nonlinear optical property of the crystal has been confirmed using the Kurtz powder technique and a study of its second harmonic generation efficiency in comparison with KDP has been made. Knoop hardness test was carried out and its Young's modulus was calculated. (C) 2009 Elsevier B.V. All rights reserved.