The synthesis and crystal structure of 4- (2' - Hydroxybenzoylhydrazinyl) benzal-5-methyl-2-phenyl-2, 4-dihydropyrazol- 3-one (B_1) and 4-(2'-hydroxybenzoylhydrazinyl) ethylidene-5-methyl-2- phenyl-2,4-dihydropyrazol-3-one (B_2) are presented in this paper. The crystal structures were determined by X-ray single crystal diffraction study. Crystal structure of B_1 belongs to monoclinic system with space group CI/c. The unit cell parameters are a = 1.4201(2) nm, b = 1.65542(2) nm, c = 1.8455(3) nm, β= 10132(1)°, V= 4.2541(10) nm~3, Z = 8, D_c= 1.344 g/cm~3, μ = 0.094 mm~(-1), F(000) = 1808, R = 0. 0442, wR = 0.1037. The water molecules bridge the adjacent stacks by the hydrogen bonds leading to the formation of supramolecular compound with two-dimensional network structure along the ac side. The crystal structure of B2 belongs to triclinic system with space group PI. The unit cell parameters are a = 1.2120(2) nm, 6 = 1.2223 (2) nm, c = 1. 4159(3) nm, a=70.38 (l)°, β= 74.91 (I)8, γ = 63.64(1)°, V=1.7549(5) nm~3, Z = 4, D_c = 1.326 g/cm~3, μ = 0.092 mm~(-l), F(000) = 736, R = 0.0436, wR = 0.1076. The supramolecule with one dimensional chain structure was formed through hydrogen bonds along the a axis. The molecules piled the layered structure along the b axis due to intermolecular interactions.

Key words: PYRAZOLINE P, HYDRAZIDE P, CRYSTAL STRUCTURE, SUPERMOLECULAR STRUCTURE