Abstract: | β-Cyclodextrin derivative 1 , bearing a group with two pyrene moieties, exhibits predominant excimer emission in a 20% DMSO aqueous solution. In spite of the fact that pyrene is too large to be included in the β-cyclodextrin cavity and consequently both pyrene moieties are located outside the cavity, 1 varies the excimer emission intensity through the formation of inclusion complexes with guest species, thus acting as a chemosensor for molecular recognition. |