Sulfonyl fluorides are now established click reagents that find broad applications in synthesis, chemical biology and drug discovery. Sulfonyl fluorides owe their popularity to their increased stability compared to their sulfonyl chloride cousins and to their high selectivity for the reaction pathway of fluoride exchange (SuFEx reaction). Other reaction pathways were unavailable to sulfonyl fluorides. However, recent reports have challenged this paradigm, showing unconventional leaving group capabilities of the whole SO2F group as part of Suzuki–Miyaura or defluorosulfonylative (deFS) couplings. This review highlights such early developments, discusses the key mechanistic aspects responsible for the alternative reactivity and recognises potential avenues for future research in this exciting new area.