The electrochemical and electrochromic properties of a variety of polysubstituted fluorene compounds have been studied. The 2, 7-and 2, 3-dimethoxy-, 2, 3, 6, 7-tetramethoxy-, and 2, 3, 4, 5, 6, 7-hexamethoxyfluorenes are highly reversible electrochromic materials. One- electron oxidation of these materials yields deeply colored, stable radical cations. The structureproperty relationships observed for the electrochemical and absorption behavior ...