This study successfully synthesized coumarins, which belong to a novel class of fused heterocyclic compounds, employing a multicomponent reaction with excellent efficiency. The process utilized 4‐aminocumarin or 4‐hydroxycumarin, 2‐arylidenemalononitrile, and activated acetylenic chemicals in an aqueous solution at room temperature in the presence of MWCNTs@SiO2/Fe3O4 as a recyclable catalyst. The synthesized compounds were assessed for their antiproliferative activity against MCF‐7 breast and HCT‐15 colon cancer cell lines using the sulforhodamine B (SRB) assay, as well as their antioxidant effect. Compounds 4c, 4g, and 6d exhibited superior antiproliferative activity compared with other synthesized compounds. The compounds 4c, 4g, and 6d were subjected to UV‐Vis spectroscopy to determine their binding affinity for DNA and BSA. The analysis yielded overall affinity constants K4c‐DNA = 7.9 × 103 M−1, K4g‐DNA = 1.1 × 104 M−1, K6d‐DNA = 4.2 × 104 M−1, K4c‐BSA = 4.96 × 104 M−1, K4g‐BSA = 7.54 × 104 M−1, and K6d‐BSA = 6.47 × 104 M−1. Our research results could offer fresh data demonstrating the correlation between the chemical composition and the ability of these novel coumarin analogs to inhibit cancer growth. The synthesis of fused coumarins exhibited various beneficial characteristics, such as fast reactions, high yields of the end product, and easy isolation of the catalyst and product from the reaction mixture.