Single crystals of semi-organic L-alanine tetrafluoroborate (L-AIFB) have been grown from aqueous solution by slow evaporation method. The crystal possesses hexagonal morphology with slight elongation along the c-axis. Powder XRD analysis confirms the orthorhombic structure of the grown crystals. The presence of borate functional groups of L-AlFB has been confirmed by FTIR analysis. On comparison with L-alanine crystals, it is found that the presence of borate functional group in L-AlFB enhances the optical transmittance and second harmonic generation (SHG) efficiency. (C) 2002 Elsevier Science B.V. All rights reserved.