The Doctoral Thesis has been prepared as a thematically united collection of scientific publications. It consists of a summary and five scientific publications. Publications have been written in English, their total volume is 39 pages. A new, selective class of CA IX and CA XII inhibitors – 3H-1,2-benzoxathiepine 2,2-dioxides, has been found. A series of 3H-1,2-benzoxathiepine 2,2-dioxide triazolyl, acylamino and aryl derivatives was synthesized. We discovered that furagin, a clinically used antibacterial agent, is a selective inhibitor of CA IX and CA XII. Developing this concept, we synthesized a series of imidazolidine-2,4-dione derivatives. Inhibitory activity on relevant human CA isoforms (I, II, IX, and XII) was determined for all products synthesized within the scope of the Doctoral Thesis.