Two syntheses of 1,1′-binaphthyl-2,2′-dicarboxylic acid (4) in good yields are presented via the oxidation of the 2′-methyl substituent of isopropyl 2′-methyl-1,1′-binaphthyl-2-carboxylate (8), which is readily obtainable by the reaction of 2-methyl-1-naphthyl Grignard reagent 7 with isopropyl 1-isopropoxy-2-naphthoate (6).