The new derivatives based on (Z)-3-(arylamino)-1-(3-phenylimidazo[1,5-a]pyridin-1-yl)prop-2-en-1-one scaffold was synthesized and evaluated for their in vitro cytotoxic potential against a panel of cancer cell lines, viz., A549 (human lung cancer), HCT-116 (human colorectal cancer), B16F10 (murine melanoma cancer), BT-474 (human breast cancer), and MDA-MB-231 (human triple-negative breast cancer). Among them, many of the synthesized compounds exhibited promising cytotoxic potential against the panel of tested cancer cell lines with IC <30 µM. Based on the preliminary screening results, the structure-activity relationship (SAR) of the compounds was established. Among the synthesized compounds, 15i displayed a potential anti-proliferative activity against HCT-116 cancer cell line with an IC value of 1.21 ± 0.14 µM. Flow cytometric analysis revealed that compound 15i arrested the G0/G1 phase of the cell cycle. Moreover, increased reactive oxygen species (ROS) generation, clonogenic assay, acridine orange staining, DAPI nuclear staining, measurement of mitochondrial membrane potential (ΔΨm), and annexin V-FITC assays revealed that compound 15i promoted cell death through apoptosis.