The chalcones 7 were utilized as building blocks for construction of pyrazole ring via their reactions with nitrogen nucleophiles such as hydrazine hydrate and phenyl hydrazine. Thus, reaction of each of chalcones 7 with hydrazine hydrate or phenyl hydrazine in refluxing ethanol in the presence of catalytic amount of acetic acid led to formation of pyrazole derivatives 8 and 9, respectively (Scheme 2). The structure assigned for each of products 8 and 9 was elucidated via elemental analysis and spectral data. The IR spectra of each of compounds 8 and 9 revealed the absence of the enone carbonyl group and showed only the presence of chromenone carboyl group at ύ = 1681-1674 cm -1 . The 1 H NMR spectra of compounds 8 and 9 revealed the absence of the signals due to the olefinic protons, and instead indicated the presence of singlet signal at δ = 7.11-6.70 ppm assigned for the pyrazole-H4, in addition to a singlet signal for products 8 appeared at δ in the region 11.20-11.22 ppm assigned to the NH proton of the pyrazole ring. The mass spectra of products 8a-d and 9a-c revealed a molecular ion peak for each one, which is consistent with the respective molecular weight.