chromophore
/krɒməˈfɔr, -ˈfoʊr/Definitions
1. noun
A part of a molecule that is responsible for its colour.
“The chromophores in the dye molecule are the groups responsible for its red colour.”
2. noun
A substance that exhibits colour due to its absorption of certain wavelengths of light.
“The chromophore in the solution changed the colour of the liquid.”