Abstract: A new compound of 4-((2-thiophenecarboxylic acid hydrazide) methylene)benzoic acid was synthesized by the reaction of ethyl 2-thiophenecarboxylate, hydrazine hydrate and 4-formylbenzoic acid，and characterized by elemental analysis, IR, UV and X-ray diffraction methods. The compound forms a 3-D network through intermolecular N—H…O and O—H…O hydrogen bondings. The dihedral angle between the benzene and thiophene ring is 14.9°. The title compound has intense purple emission at 396 nm when excited at 286 nm. The result of TG/DTG analysis showed that the title compound was stable below 298 ℃ in N2. The quantum chemical calculation was performed by means of Gaussian 03W program. The Mulliken charge population and Wiberg bond order of the compound and its frontier molecular orbital energy have been discussed. Furthermore, we analyzed its active atoms and evaluated its reliability. The results showed that the values of the bond lengths and bond angles of the quantum chemical calculation were almost the same with the values of X-ray diffraction. The difference between the two methods confirmed the presence of intermolecular hydrogen bonds in their crystal structures. The carbonyl groups are the active centers. CCDC:821263

Key words: Hydrazides, formylbenzoic acid, crystal structure, luminescent property, thermal stability, Quantum chemistry