We herein describe a new synthesis of N-(7-indazolyl) benzenesulfonamide derivatives. These compounds were evaluated for their antiproliferative activities toward L1210 murine leukemia cells. One of them, 4-methoxy-N-(3-chloro-7-indazolyl) benzenesulfonamide, was identified as the most potent with an IC50 of 0.44 μM.