Synthesis and Electronic Transitions of the Dye Based on 1-{2-[4-(3-Hydroxy-2-oxo-2H-chromen-4-yl)phenyl]-2-oxoethyl}-4-methylpyridinium Bromide

4-[4-(2-Bromoacetyl)phenyl]-3-hydroxy-2H-chromen-2-one reacted with pyridine and 4-methylpyridine to give the corresponding quaternary pyridinium salts. The condensation of 1-{2-[4-(3-hydroxy-2-oxo-2H-chromen-4-yl)phenyl]-2-oxoethyl}-4-methylpyridinium bromide with 4-(dimethylamino)benzaldehyde afforded a new biscyanine dye whose electronic spectrum showed two absorption maxima originating from interactions of chromophores. The nature of electronic transitions in the dye molecule was analyzed by quantum chemical calculations.