Aromatic carboxylic acids have been recognized as important building blocks in organic synthesis field because of their wide availability and easy handling. Their carboxy group is known to act as a directing group in transition-metal-catalyzed C-H functionalization. For example, ortho-substituted benzoic acids undergo iridium-catalyzed dehydrogenative coupling with alkynes at the opposite ortho- and meta-positions accompanied by decarboxylation. Exceptionally, salicylic acid couples with alkynes at the ipso- and ortho-positions to produce 5,6,7,8-tetrasubstituted 1-naphthol derivatives. 1-Naphthoic acid reacts with diphenylacetylene under rhodium catalysis at the 2- and 3-positions selectively to afford 1,2,3,4-tetraphenylanthracene. In contrast, 9-anthracenecarboxylic acid exhibits unique reactivity. Treatment of this substrate with diphenylacetylene under rhodium catalysis does not give any intermolecular coupling products at all but gives an intramolecular C-O coupling product. 9-Anthracenecarboxylic acid also undergoes palladium-catalyzed dehydrogenative coupling with styrenes at the peri position and successive Wacker-type cyclization to produce (Z)-3-benzylidenedibenzo[de,h]isochromen-1-one derivatives.