Abstract: The synthesis and spectroscopic characterisation of some representative N-alkyl- substituted quaternary ammonium salts derived from benzothiazole, benzoxazole, benzo- selenazole, indole and quinoline are described. These heterocyclic salts, bearing an activated methyl group in the 2-position in relation to the nitrogen atom and N-methyl,-pentyl,- hexyl and-decyl chains, are typical precursors of cyanine dyes.
