Compounds having their chemical structure based on coumarin framework have enticed much research concern not only because of the variance structural characteristic but also the pluralism of the bioactivities. In this report, four derivatives of 7-halo-4-coumarinylacetic acid referred to as RY1-RY4 were synthesized, and their chemical backbones were confirmed via the employed spectrophotometers. The pharmacokinetic profiles of the synthesized halocoumarins were inspected in silico using a free online software named the pre-ADMET program. The potential of the synthesized halocoumarins as antitumor applicants was evaluated utilizing 5-fluorouracil as a reference drug and the well-authenticated protocol based on the MTT as a visible indicator against eight standard tumor-cell lines. The outcomes acquired from this assessment indicated that the synthesized halocoumarins, except RY1, have less impact as antitumor agents comparing with the standard drug. Also, the halocoumarins revealed roughly the same fashion of activity versus the test cell lines with the greatest inhibitory influence reported against MCF-7 and HeLa. From the calculated pharmacokinetic data and outcomes exhibited from antitumor assessment, the authors concluded that the synthesized halocoumarins, particularly RY1, offered potential applicants as antitumor agents with broad-ranged activity. Besides, the compounds RY1 and RY2 may provide highly valuable scaffolds for synthesizing agents with a powerful antitumor activity versus the breast and cervical cancer phenotypes.