Truxinic acids are any of several stereoisomeric cyclic dicarboxylic acids with the formula (C6H5)2C4H4(COOH)2, found in various plants.

[1][2] They are obtained by a photochemical cycloaddition from cinnamic acid,[3] where the two trans alkenes react head-to-head.

Ten stereoisomers are possible.

[4][5]