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<div><p>Multidrug resistance (MDR) mechanisms in cancer cells are greatly influenced by glutathione transferase P1-1 (hGSTP1-1). The use of synthetic or natural compounds as hGSTP1-1 inhibitors is considered an effective approach to overcome MDR. Nine compounds consisting of coumarin-6-sulfonamide linked to chalcone derivatives were synthesized and evaluated for their ability to inhibit hGSTP1-1. Among the synthetic derivatives, compounds <b>5g</b>, <b>5f</b>, and <b>5a</b> displayed the most potent inhibitory effect, with IC<sub>50</sub> values of 12.2 ± 0.5 μΜ, 12.7 ± 0.7 and 16.3 ± 0.6, respectively. Kinetic inhibition analysis of the most potent molecule, <b>5g</b>, showed that it behaves as a mixed-type inhibitor of the target enzyme. An <i>in vitro</i> cytotoxicity assessment of <b>5a</b>, <b>5f,</b> and <b>5g</b> against the human prostate cancer cell lines DU-145 and PC3, as well as the breast cancer cell line MCF-7, demonstrated that compound <b>5g</b> exhibited the most pronounced cytotoxic effect on all tested cell lines. Molecular docking studies were performed to predict the structural and molecular determinants of <b>5g</b>, <b>5f</b>, and <b>5a</b> binding to hGSTP1-1. In agreement with the experimental data, the results revealed that <b>5g</b> exhibited the lowest docking score among the three studied inhibitors as a consequence of shape complementarity, governed by van der Waals, hydrogen bonds and a π-π stacking interaction. These findings suggest that coumarin-chalcone hybrids offer new perspectives for the development of safe and efficient natural product-based sensitizers that can target hGSTP1-1 for anticancer purposes.</p></div>