A molecular dyad has been synthesized in which the main chromophore is a 1, 4- diethynylated benzene residue terminated with pyrene moieties, this latter unit acting as a single chromophore. A spiropyran group has been condensed to the central phenylene ring so as to position a weak electron donor close to the pyrene unit. Illumination of the pyrene- based chromophore leads to formation of a fluorescent exciplex in polar solvents but ...
