Reaction of alpha-methoxyacetic acid with aromatic compounds in the presence of trifluoroacetic anhydride and Lewis acid has been found to give diarylmethanes. Some of the intermediates in this transformation have been identified via direct observation by H-1 and C-13 NMR spectroscopy. The reaction route has been clarified as follows: a mixed acid anhydride is formed from a-methoxyacetic acid and trifluoroacetic anhydride, which gives a hemiacylal type intermediate via decarbonylation followed by successive double electrophilic aromatic substitutions yielding diarylmethanes.