We report an electrochem. transformation of binaphthols to give peri-xanthenoxanthene (PXX) groups in small mols. and within polymer backbones. The monomer 7,7'-bis(2,2'-bithiophen-5-yl)-1,1'-bi-2,2'-naphthol (2) was subjected to electropolymn., resulting in the segmented conducting polymer that is stable at low potentials. However, high-potential electrochem. oxidn. promoted cyclization of binaphthol units gives PXX, which transforms the moderately conducting segmented polymer into a highly conducting fully conjugated polymer. This oxidative cyclization is a highly effective means by which to incorporate a planar polycyclic heteroarom. structure (i.e., PXX) into thiophene-based conducting polymers. A model compd. study conclusively proved the proposed oxidative cyclization scheme. [on SciFinder(R)]