Lecanoric acid is a chemical produced by several species of lichen. Lecanoric acid is classified as a polyphenol and a didepside and it functions as an antioxidant. The acid is named after the lichen Lecanora. The acid has also been isolated from , Parmotrema stuppuem, Parmotrema tinctorum, , Xanthoparmelia arida and Xanthoparmelia lecanorica. A related compound, 5-chlorolecanoric acid, is found in some species of Punctelia.