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The <i>C</i>(sp²)-aryl sulfonate functional group is found in bioactive molecules, but their synthesis can involve extreme temperatures (>190 °C or flash vacuum pyrolysis) and strongly acidic reaction conditions. Inspired by the 1917 Tyrer industrial process for a sulfa dye that involved an aniline <i>N</i>(sp²)-SO₃ intermediate <i>en route</i> to a <i>C</i>(sp²)-SO₃ rearranged product, we investigated tributylsulfoammonium betaine (TBSAB) as a milder <i>N</i>-sulfamation to <i>C</i>-sulfonate relay reagent. Initial investigations of a stepwise route involving TBSAB on selected anilines at room temperature enabled the isolation of <i>N</i>(sp²)-sulfamate. Subsequent thermal rearrangement demonstrated the intermediary of a sulfamate <i>en route</i> to the sulfonate; however, it was low-yielding. Investigation of the <i>N</i>-sulfamate to <i>C</i>--sulfonate mechanism through control experiments with variation at the heteroatom positions and kinetic isotope experiments (KIE^H/D) confirmed the formation of a key <i>N</i>(sp²)-SO₃ intermediate and further confirmed an <i>inter</i>molecular mechanism. Furthermore, compounds without an accessible nitrogen (or oxygen) lone pair did not undergo sulfamation- (or sulfation) -to-sulfonation under these conditions. A one-pot sulfamation and thermal sulfonation reaction was ultimately developed and explored on a range of aniline and heterocyclic scaffolds with high conversions, including <i>N</i>(sp²)-sulfamates (<i>O</i>(sp²)-sulfates) and <i>C</i>(sp²)-sulfonates, in up to 99 and 80% (and 88% for a phenolic example) isolated yield, respectively. Encouragingly, the ability to modulate the <i>ortho-para</i> selectivity of the products obtained was observed under thermal control. A sulfonated analog of the intravenous anesthetic propofol was isolated (88% yield), demonstrating a proof-of-concept modification of a licensed drug alongside a range of nitrogen- and sulfur-containing heterocyclic fragments used in drug discovery.