A series of -aryl-7-aryl-pyrazolo[1,5-]pyrimidines ⁻ and -aryl-pyrazolo[1,5-]quinazolines ⁻ were designed and synthesized via the reaction of 5-aminopyrazoles ⁻ with enaminones ⁻ or , respectively. The new compounds were screened for their in vitro antitumor activity toward liver (HepG-2) and breast (MCF-7) human cancer cells using 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-tetrazolium bromide MTT assay. From the results, it was found that all compounds showed dose-dependent cytotoxic activities against both HepG-2 and MCF-7 cells. Two compounds and were selected for further investigations. Cell cycle analysis of liver (HepG-2) cells treated with and breast (MCF-7) cells treated with showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.