“…The extended framework of a typical ionic liquid (IL) neutralizes the innate ion charge separation between the cation, typically ammonium of general formula R 4 N + , and the anion, typically a highly delocalized perfluorinated counteranion XF n – [i.e., BF 4 – , PF 6 – , or TFSI – (bis(trifluoromethanesulfonyl)imide)], thus keeping the material neutral and without acidity. − In stark contrast, the corresponding perfluorinated Brönsted acids and also the metal salts prepared thereof by halide metathesis, with general formula MXF n , show some of the higher acidity values recorded so far, active as superacid catalysts (pH < H 2 SO 4 ) in organic reactions. − In order to use the IL as an acid catalyst and a solvent, additional chemical modifications if not the partial decomposition of the IL have been reported, such as the generation of protons by partial hydrolysis, − the addition of metal nanoparticles or external acids, − and the incorporation of sulfonic, carboxylic, and metal anion functions into the IL chemical structure, which have been named Brönsted (BAILs) and Lewis acidic ionic liquids (LAILs), respectively . However, all these strategies require the permanent modification of the original IL structure, increasing significantly the costs for the acid function synthesis and just overlooking the innate acidity of ILs.…”