The processes of the intramolecular charge transfer in the series of the trans-isomers of styryl derivatives of pyridines and quinolines N-oxides possessing substituents with +M effect are investigated. Complex formation of these compounds with Bronsted-Lowry acids is studied by the methods of IR, electronic and 1H NMR spectroscopy. The center of protonation and formation of hydrogen bond with the N-oxides dimethylamino derivatives is determined by the nature of the solvent (in water the first protonation occurs at the amino group, in the organic solvents at the group N→O). Composition and structure of molecular complexes depends on the nature of the complex forming compounds and the ratio of reagents.