Threonine Schiff base derived 2-hydroxy-1-naphthaldehyde and threonine has been isolated and investigated. The stoichiometry of this compound was derived from the results of elemental analyses, IR, H-1-NMR and UV spectroscopic techniques. X-ray diffraction method was also used to obtain the single-crystal structure. The compound crystallizes in the space group P2(1) with cell dimensions a = 5.109(2), b = 11.334(2), c = 11.155(3) Angstrom and beta = 91(3)degrees with Z = 2. The molecule has phenol-imine tautomeric form in the crystal structure. Some of bond lengths and angles found in the molecular structure are distorted due to pi-electron delocalization and steric effect of naphthylidene and threonine groups. (C) 2003 Elsevier B.V. All rights reserved.