merocyanine
/ˌmɛrə(ʊ)ˈsʌɪəniːn/Chemistry
noun
Any of a class of neutral dyes, many of which are used as sensitizers for photographic emulsions, in which a nitrogen atom (usually part of a basic heterocycle) is linked to a carbonyl group (usually part of an acidic heterocycle) by a conjugated chain of carbon atoms.
Origin
1930s. From mero- + cyanine, because these dyes have part of the structure of cyanine dyes.