In biology, a light-harvesting complex or LHC is an aggregate consisting of proteins bound with chromophores (chlorophylls and carotenoids) that play a key role in photosynthesis. LHCs are arrayed around photosynthetic reaction centers in both plants and photosynthetic bacteria and collect more of the incoming light than would be captured by the reaction centers alone. The light captured by the chromophores excites molecules from their ground states to (short-lived) higher-energy states, known as the excited states. This energy is then focused toward the reaction centers by Förster resonance energy transfer.
Light-harvesting complexes are found in a wide variety among the different photosynthetic species, with no homology among the major groups.