By using salicyloylhydrazine and o-carboxybenzaldehyde salicyloylhydrazone, o-carboxybenzaldehyde salicyloylhydrazone (C₁₅H₁₂O₄N₂) was synthesized and characterized by elemental analysis, IR, ¹H NMR and single-crystal X-ray diffraction. The crystal structural analysis shows that the compound crystallizes in a monoclinic lattice, space group C2/c with a＝19.352(8) ?, b＝14.219(8) ?, c＝12.762(3) ?, β＝115.605(14)°, V＝3167(3) ?³, Z＝8, F (000)＝1344, D_c＝1.344 Mg/m³. The compound molecules are linked by hydrogen bond (N—H…O) between two benzene rings, and the compound is wrapped into an infinite chain of double helix. Thermal gravity analysis indicate that the compound has two decomposition stages, the decomposition endothermic peak appears at 232.64 ℃ in the second stage. Its antibacterial activity was tested against Escherichia coli. The results show that the compound has good antibacterial activity.

Key words: synthesis, crystal structure, thermal stability, antibacterial activity, o-carboxybenzaldehyde salicyloylhydrazone