A series of fourteen novel 1,3,4-triarylpyrazoles were synthesized and evaluated for their antiproliferative activity against human breast cancer MCF7 cell line. Cells were exposed to different concentrations of compounds (0.1, 10, 100, 1000 μM) for 72 hours. Then the viability of treated cells was determined using MTT technique. Compound 7a was found to exhibit significant antiproliferative activity (IC50 = 6.95 μM). Using flow cytometric analysis, compound 7a was observed to induce apoptosis and to block the cell cycle at G2/M phases in MCF7 cells. 3D-Pharmacophore modeling and quantitative structure-activity relationship (QSAR) analysis were combined to explore the structural requirements controlling the observed anti-tumor properties.