A pigment is a molecule that absorbs certain energy, or wavelengths, of light and reflects all others. An accessory pigment is a light-absorbing compound that occurs in photosynthetic organisms, or repositories of energy, and works with chlorophyll a, which is the most important pigment that occurs in green plants. Some accessory pigments include forms of chlorophyll a, such as chlorophyll b, and others do not include forms of chlorophyll a, such as carotenoids.
Xanthophylls and Anthocyanins and carotenoids are the pigments other than chlorophyll that can absorb sunlight.