Reversible synthesis and characterization of dynamic imino analogues of trimethine and pentamethine cyanine dyes.

A new family of unsymmetrical imine-based trimethine and pentamethine cyanine dye analogues is reported that can form under reversible and thermodynamically controlled conditions from non- or weakly emissive amine and aldehyde building blocks. These dynamic fluorophores show spectroscopic properties comparable to those of their parent cyanine dyes and are responsive to external effectors.