ore interestingly, this behavior is

ore interestingly, this behavior is also true for all the five anionic surfactants at all the examined concentrations either below or above their CMC (Fig. S11, ESI). Just as found for SDS, the dual-chromophore displays both pyrene and rhodamine emission in these anionic surfactant assemblies, and increasing surfactant concentration leads to reduction of pyrene excimer emission and varies the ratio of pyrene excimer to rhodamine emission. A specific phenomenon should be noted is that the degree of fluorescence variation is different from surfactant to surfactant as evidenced by the various emission profiles in these anionic surfactants. Thus, the dual-chromophore displays typical multiplewavelength cross-reactive responses to different anionic surfactants, which makes it possible to realize pattern recognition and discrimination among anionic surfactants.