Application： Croconic acid is used to prepare 1,3-bis-(2-dimethylamino-5-thienyl)croconine by reacting with dimethyl-thiophen-2-yl-amine. It is also used in organic synthesis and employed as a dye for biological research purposes. Further, it is involved in the preparation of ethers such as dimethyl croconate. In addition to this, it acts as a ligand and form coordination complexes with metals such as barium, copper, silver and lead.