Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, for the first time the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in 1 step from amines and disulfides. A highly chemoselective and one-pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, including the functionalization of anti-depressants desipramine and fluoxetine. Additionally, the methodology is applied to the preparation of an aza-analogue of the drug probenecid, with further N-functionalization reactions exemplified on this scaffold. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy-amino-λ6-sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles. Detailed mechanistic studies demonstrate the iPrOH as one source of the sulfonimidamide oxygen atom, in addition to water and acetate.