Regulates the blue-light dependent dimerization of CRY2 and formation of photobodies. Interacts with photoexited CRY2 to inhibit its activity. Inhibits CRY phosphorylation. Interacts with CRY2 in both darkness and light. No visible phenotype. Bic1 and bic2 double mutants have a blue light-hypersensitive short-hypocotyl phenotype and an increased anthocyanin accumulation when grown in continuous blue light.