single-color off-on and on-off fluorescent switches interconvert between emissive and nonemissive states. Among them, off-on systems are preferred for optical sensing, [11,23,24] as higher sensitivities can be reached by detecting tiny fluorescence signals above a dark background. On the contrary, on-off switches are exploited in super-resolution fluorescence microscopy, which typically requires reversibly extinguishing the emission of fluorophores either in time (in coordinate-stochastic methods) [25,26] or space (in coordinate-targeted methods). [27,28] On the other hand, dualcolor fluorescent switches are designed to toggle between two differently colored emissive states (on 1 -on 2 ), [17] a behavior that offers several advantages for sensing and anti-counterfeiting applications (e.g., reduced interference from the autofluorescence of the medium, [22] quantitative ratiometric measurements, [22,29] and multiple readout modes for higher security levels [18,20] ).