hCA/VEGFR-2-IN-4 (compound 15b), an indolinylbenzenesulfonamide, serves as a potential dual inhibitor targeting cancer-related human carbonic anhydrases hCA IX/XII and vascular endothelial growth factor receptor 2 (VEGFR-2). It exhibits an IC50 value of 0.811 µM against VEGFR-2 and demonstrates high affinity for hCAs, with inhibition constants (Ki) of 3.8 nM for hCA XII, 6.2 nM for hCA IX, 19.8 nM for hCA II, and 35.5 nM for hCA I. Additionally, the compound shows antiproliferative effects on breast cancer cells overexpressing VEGFR-2 [1].