“…During the last two decades, C–H activation chemistry has gained widespread attention, because it provides an atom- and step-economical route for preparing not only complex molecules, such as natural products and pharmaceuticals, − but also fluorophores that can be applied in organic light-emitting diodes (OLEDs). − In the field of C–H activation chemistry, C–C bond formation has been mainly studied so far, but recently, direct C–H amination/amidation strategies resulting in C–N bond formation have also been actively investigated. − Among them, Chang’s group developed iridium-catalyzed direct C–H amidation (DCA) reactions between sulfonyl azides and arenes containing carbonyl (or imine) directing groups, thus enabling efficient synthesis of various sulfonamides under mild conditions (Scheme a). ,,− Inspired by the highly efficient DCA, we recently reported direct C–H amidation polymerization (DCAP) of bis-sulfonyl azides and bis-benzamides to produce polysulfonamides by an atom-economical and green method (Scheme b). , Interestingly, unique intramolecular hydrogen-bonds are formed between the proton on the sulfonamide group and adjacent carbonyl group throughout the polymer backbone, causing polysulfonamides to undergo an excited-state intramolecular proton-transfer (ESIPT) process and emit blue-light with high quantum yields. This process occurs when photoexcited molecule emits light with a very large Stokes shift by transfer of protons, leading to keto–enol tautomerization.…”