[a] Isolated yield. From the viewpoint of atom-economy, we chose entry 3 in Table as the optimal conditions, and next examined the scope of the reaction (Scheme 2). First, several symmetrical diphenylacetylenes 1b-1j were examined. The anodic oxidation of 1b, bearing dimethyl groups at the 4,4'-positions, afforded 2,7-dimethyl-BTBT 2b in 68% yield. 3,8-Dimethyl-BTBT 2c was obtained from 1c bearing dimethyl groups at the 5,5'-positions in moderate yield. Halogenated substrates were next examined. 2,7-Dichloro-BTBT 2d was obtained in 29% yield, but 3,8dichloro-BTBT 2e was not obtained under the reaction conditions. A similar tendency was observed in the synthesis of dibromo-BTBTs 2f and 2g. In contrast, the electrochemical reaction of 1h bearing difluoro groups proceeded smoothly to afford difluoro-BTBT 2h in 71% yield. 4,4'-Dicyanodiphenylacetyelene 1i was not suitable for the reaction, but 1j, diphenylacetylene bearing two trifluoromethyl groups, gave bis(trifluoromethyl)-BTBT 2j in 75% yield. We next studied the electrochemical synthesis of mono-substituted BTBT derivatives (2k-2v). BTBT derivatives bearing electro-donating groups such as methyl, isopropyl, and tert-butyl groups, were obtained in moderate to good yields (2k-2n). We next examined the electrochemical reaction of diphenylacetylenes 1o-1v which have electron-withdrawing groups. BTBT derivatives bearing halogen atoms were obtained in low to high yields (2o-2t). BTBTs bearing cyano and trifluoromethyl groups were readily obtained by this method and the corresponding products were obtained in yields of 78% and 81%, respectively (2u and 2v). BTBT derivatives 2w and 2x, which have two different functional groups, could also be synthesized by this method with the use of the corresponding substrates 1w and 1x. As described above, this method enables us to access to a variety of BTBT derivatives which have electron-donating and -withdrawing groups. N.D. N.D. 4 50 66 (84) N.D. N.D.