Solid-state fluorescence of pyridinium styryl dyes

•A series of new pyridinium styryl dyes have been synthesized.•The most intense solid-state fluorescence was observed at 652 nm (Φf = 0.16).•The solid-state fluorescence behavior is attributed isolated dimer-type packing.

1-Alkyl-2-[4-(diethylamino)styryl]pyridinium salts showed fluorescence maxima at around 650 nm in the solid state depending on the alkyl group and counter anion. 1-Butyl-2-[4-(diethylamino)styryl]pyridinium bis(perfluorobutylsulfonyl)imide exhibited the fluorescence maximum at 652 nm with the highest quantum yield 0.16 in the crystalline form. The single X-ray crystallography suggests that this compound exhibits isolated dimer-type packing leading to fluorescence in the solid state.

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