Used primarily as a reagent in organic synthesis to form 4-iodobenzenesulfonyl hydrazones from aldehydes and ketones. These hydrazones serve as key intermediates in named reactions such as the Shapiro reaction (for regioselective alkene synthesis) and Bamford–Stevens reaction (for diazo transfer and carbene generation). The para-iodo substituent facilitates further derivatization via cross-coupling reactions (e.g., Sonogashira, Heck). Commonly applied in pharmaceutical research for antibacterial and antimicrobial drug candidates, as well as in the preparation of dyes, pigments, and other fine chemicals. Highly valued in R&D for developing novel entities with industrial and medicinal potential.