. 69, 1457 (1991).Semihydrogenation of 1,2-bis(3,4-dicyanopheny1)ethyne gave cis-1,2-bis(3,4-dicyanopheny1)ethene. From these precursors, binuclear phthalocyanines were produced containing linear binuclear phthalocyanines having an ethyne bridge and a mixture of cis and trans isomers of binuclearphthalocyanines linked by an ethene bridge. The cis and trans isomers could be separated and differentiated by gel permeation chromatography as the very extended trans isomer elutes faster than the cofacial globular cis isomer. Strong coupling between the conjugated binuclear phthalocyanine was not observed when examined by cyclic voltammetry. Introduction It has been shown (1-4) that binuclear porphyrins, constrained to lie in cofacial configurations, are effective in catalyzing the 4e reduction of O2 to H20. The long-term instability of these porphyrin catalysts, however, has led us to prepare the more stable cofacial binuclear and multinuclear (5-7) phthalocyanines (8-lo), having bridges of five (5,8), four (6), three (7), two (6), one (9), zero (7), and even "(-1)" bridges (10). The electrochemistry of some of these cofacial(7, 11) and conjugated planar (10) metallophthalocyanines exhibted interesting mixed valence species, but only the 2e reduction of O2 was observed, albeit with greater efficiency than mononuclear species. We had never attempted to prepare a binuclearphthalocyanine that is both conjugated and cofacial but we have now succeeded in this quest and report its synthesis, and its spectroscopic and electrochemical properties.