An imidazolium salt was grafted to cellulose nanocrystals (also called nanowhiskers) using copper(I) catalysed azide-alkyne cycloaddition and the bromide anion was successfully exchanged for bistriflimide and an anionic dye, providing the opportunity to synthesize a wide variety of ion exchange systems or catalysts using cellulose nanocrystals as a support medium.