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E-Isomers of styryl dyes containing a benzo-18-crown-6 ether or N-methylbenzoaza-18-crown-6 ether moiety and a benzothiazolium residue with an ammoniohexyl, ammoniopentyl, or ammoniomethylbenzyl N-substituent were synthesized. According to spectrophotometry and NMR spectroscopy data, dyes of this type are capable of self-assembly in MeCN to form dimeric complexes, which have a pseudocyclic structure owing to double intermolecular ammonium cation–crown ether interactions via hydrogen bonds; the dimerization equilibrium constants were measured. It was shown that photoinduced Z-isomers of the dyes are capable of intramolecular complex formation between the ammonium cation and the crown ether moiety; therefore, upon E→Z photoisomerization, the dimer–monomer equilibrium shifts towards the pseudocyclic monomer. Data on the relative stability of the intramolecular cation-capped complexes formed by Z-isomers were obtained. It was shown that the equilibrium constants for the Ba2+ complexation with E-isomers of the dyes are almost three orders of magnitude higher than those for that with Z-isomers, which may imply the applicability of these dyes as photoswitchable supramolecular devices. [ABSTRACT FROM AUTHOR]