The synthesis of 3,4-alkoxythieno[2,3-b]thiophene derivatives has been developed from the readily accessible dimethyl or diethyl 3,4-dihydroxythieno[2,3-b]thiophenedicarboxylates. The yields for the dialkoxy derivatives were strongly dependent both on the base and the alkylating agent used for the nucleophilic substitutions. A trimer associating the new 3,4-ethylenedioxy-thieno[2,3-b]thiophene unit with 3,4-ethylenedioxythiophene moieties has been synthesized and electropolymerized.