Highly fluorescent benzofuran derivatives of the GFP chromophore

Intramolecular cyclization reactions of Green Fluorescent Protein chromophores (GFPc) containing an arylethynyl ortho-substituent at the phenol ring provide new aryl-substituted benzofuran derivatives of the GFPc. Some of these heteroaromatic compounds exhibit significantly enhanced fluorescence at red-shifted emission wavelengths relative to the parent GFPc structure.