Used as a key reagent in organic synthesis, particularly in the preparation of thiocarbonyl compounds. It serves as a chlorothionoating agent, enabling the introduction of the thiocarbonyl group into alcohols and amines, forming intermediates like thiocarbamates and thiocarbonates. Commonly applied in the development of pesticides, pharmaceuticals, and agrochemicals due to its ability to modify functional groups with sulfur. Its reactivity makes it valuable in synthesizing heterocyclic compounds and in peptide chemistry for protecting group manipulation. Handle with care due to high reactivity and moisture sensitivity.