Used as a highly reactive sulfonylating agent in organic synthesis, particularly in the preparation of sulfonamide derivatives which are key intermediates in pharmaceuticals and agrochemicals. It is also employed in the development of novel functional materials and polymer modifiers due to its ability to introduce fluorosulfonyl groups into aromatic systems. Its reactivity makes it valuable in click chemistry and in the synthesis of ionic liquids or proton exchange membranes for fuel cell applications. Handle with care due to high toxicity and moisture sensitivity.