Abstract 2-(3, 4, 5, 6-Tetrafluoro-2-hydroxyphenyl) benzoxazole (2) emits the long wavelength fluorescence around 500 nm in nonpolar solvent via the intramolecular proton transfer process in the excited state of 2 (enol-form) and also emits the intermediate wavelength fluorescence around 440 nm in polar solvent, which is assumed to originate from the excited state of 2 (anion). The ease of formation of 2 (anion), compared to 2-(2- ...
