Abstract: Pyrolysis of 3, 4-bis (acetoxymethyl)-2, 5-dimethylfuran (8) gives a 12% yield of a [4+ 21 dimer (10) of furanoradialene (4). A similar pyrolysis of 3, 4-bis (benzoyloxymethyl)-2, 5-dimethylfuran (9) gives 10 in 69% yield. Low-temperature'H and" C NMR spectral studies show that 4 is the primary pyrolysis product from 8 and 9, which forms 10 upon warming. Pyrolysis of 3, 4-bis [acetoxydideuteriomethyl]-2, 5-dimethylfuran (84) gives [4+ 21 dimer ...