In the present study, a series of coumarin derivatives were designed, synthesized and evaluated for their antioxidant and cytotoxic properties. The title compounds, 2-(3-substituted-4-methyl-2-oxo-2H-chromen-7-yloxy)-2-methylpropanoic acid derivatives 5a–5f, were synthesized by base-catalyzed dehydrohalogenative cyclization following Hantzsch synthesis. All the newly synthesized analogues were characterized and established on the basis of mass, ¹H NMR, ¹³C NMR and IR studies. The compounds were evaluated for their in vitro antioxidant activity and found to exhibit substantial activity. The in vitro cytotoxicity was evaluated against MCF-7, MDA-231 (human breast cancer) and HT29 (human colon adenocarcinoma) cell lines by MTT assay and the results were encouraging. Compound 5b, with lower IC₅₀ values of 2.4 and 4.8 μM for MCF-7 and MDA-231, respectively, was considered to be potent among the series.