Discrimination of Anionic Polysaccharides via Monomer-Excimer Switching and Photo-Induced Colorimetric Reaction of 1-Methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium

1-Methyl-3-(N-(1,8-naphthalimidyl)ethyl)imidazolium can be a discriminator for anionic polysaccharides via monomer-excimer switching and photo-induced colorimetric reaction. In the system, the excimer fluorescence increases remarkably in the presence of sulfated polysaccharides. The degree of enhancement depends on the number of sulfate groups in its structure. In contrast, the degree of excimer enhancement is not significant in the presence of carboxylated polysaccharides probably due to a different photo-induced decay pathway. The solutions containing carboxylated polysaccharides certainly become yellow via a photo-induced colorimetric reaction.