Aromatic acids are a type of aromatic compound. Included in that class are substances containing an aromatic ring and an organic acid function (C6-C1 skeleton). There are several categories of aromatic acids including:

• Phenolic acid: substances containing an aromatic ring and an organic carboxylic acid function (C6-C1 skeleton).
• Hydroxycinnamic acids, molecules with the C6-C3 skeleton: a-cyano-4-hydroxycinnamic acid, caffeic acid, cichoric acid, cinnamic acid, chlorogenic acid, diferulic acids, coumaric acid, coumarin, ferulic acid, sinapinic acid
• Aromatic amino acids