Interesting inhibitory activities were observed against all these isoforms. hCA I, an isoform involved in several eye diseases was inhibited moderately with K<sub>I</sub>s in the range of 191.8-904.2 nM, hCA II, an antiglaucoma drug target was highly inhibited by the new sulfonamides, with K<sub>I</sub>s in the range of 0.75-8.8 nM. hCA IX, a tumor-associated isoform involved in cancer progression and metastatic spread was potently inhibited by the new sulfonamides, with K<sub>I</sub>s in the range of 2.3-87.3 nM, whereas hCA XII, and antiglaucoma and anticancer drug target, was inhibited with K<sub>I</sub>s in the range of 6.1-71.8 nM.