A series of extraordinarily long oligothiophenes up to the 96-mer has been developed by iterative oxidative coupling of the completely beta-blocked sexithiophene. They are highly conjugated like nonsubstituted oligothiophenes, and the effective conjugation of this system is extended to 96 thiophene units and much longer than that previously speculated for polythiophenes.

[reaction: see text] A series of oligo(octithienylene-diethynylene)s alternately composed of octithiophene and diacetylene units have been prepared by a random Eglinton coupling reaction among mono- and diethynyloctithiophenes. The largest compound isolated in the oligomeric series is comprised of twelve octithiophene units and eleven diacetylene units, and its molecular length reaches ca. 43 nm, which is the longest among single-component conjugated nanomolecules.

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