cyanine dye(n = noun.substance) - any of a class of dyes containing a -CH= group linking two heterocyclic rings containing nitrogen; used as sensitizers in photography;
is a kind of dye, dyestuff

acid dye, aniline dye, azo dye, basic dye, cyanine, direct dye, double dye, dye, fast dye, fluorescent dye, hair dye, lac dye, metallized dye, radiopaque dye, substantive dye, vat dye