Used as a mild and efficient sulfonating agent in organic synthesis, particularly for the sulfonation of aromatic compounds and sensitive substrates. It offers better control and reduced side reactions compared to free sulfur trioxide. Commonly employed in the pharmaceutical and agrochemical industries for introducing sulfonic acid groups into molecules. The complex stabilizes sulfur trioxide, making it safer and easier to handle in laboratory and industrial settings. Also utilized in the production of surfactants and dyes due to its reliable reactivity and solubility in polar organic solvents.