Abstract: Three titled compounds namely (E)-N'-(2-hydroxybenzylidene)-3,4,5-trimethoxybenzohydrazide (1), (E)-N'- (5-bromo-2-hydroxybenzylidene)-3,4,5-trimethoxybenzohydrazide (2) and (E)-N'-(4-cholobenzylidene)-3,4,5- trimethoxybenzohydrazide (3) have been synthesized, and characterized by IR and ¹HNMR.Their crystalline and molecular structures have been determined by single crystal X-ray diffraction. Both compounds 1 and 2 belong to monoclinic system, space group P2(1)/c, with a=1.5348(12)nm, b=1.3330(11)nm, c=0.8299(7)nm,α=90.00°,β=99.854(16)°,γ=90.00°, V=1.6730(2)nm³, Z=4, Dc=1.312g/cm³,F(000)=696,R=0.1016, wR=0.1936, for compound 1; a=1.14157(19)nm, b=1.6279(3)nm, c=0.9738(16)nm,α=90.00°, β=100.210(16)°,γ=90.00°,V=1.7144(4)nm³,Z=4, Dc=1.586g/cm³, F(000)=832,R=0.0669,wR=0.0969 for compound 2. Compound 3 belongs to triclinic system, space group P-1, with a=0.5119(2)nm, b=0.8210(4)nm, c=2.0276(9)nm, α=101.055(7)°,β=92.362(7)°,γ=101.459(7)°, V=0.8169(7)nm³,Z=2, Dc=1.418g/cm³,F(000)=364, R=0.0516, wR=0.1276. In the crystals there exist several intermolecular hydrogen bonds, through which one-dimensional infinite-chain structures were formed.

Key words: (E)-N'-(2-hydroxybenzylidene)-3, 5-trimethoxybenzohydrazide, (E)-N'-(5-bromo-2-hydroxy-benzylidene)-3, 5-trimethoxybenzohydrazide, (E)-N'-(4-cholobenzylidene)-3, 5-trimethoxybenzohydrazide