Potassium Ion Selective Signaling Based on Intramolecular Dimer Formation of Biscrown Ether Azochromophore —Chemosensor Exhibiting Forceps Function—

A novel bisbenzo-15-crown-5 azochromophore, 2, which exhibits forceps function, has been designed. 2 shows selective UV–vis spectral response for K+ in acetonitrile, which is based on the exciton interaction of the two azochromophores upon forming an intramolecular sandwich complex with K+.