By using selectively 13C-labeled sulfinyl and Gilch polymers, only noneliminated groups were demonstrated to be present in significant amounts (ca. 6.9%) in the sulfinyl conjugated OC1C10-PPV. By means of a two-step elimination procedure, this amount could be reduced to a level less than 0.5%. In the Gilch route on the other hand, a tolane-bisbenzyl unit was confirmed to be the main structural defect. Furthermore, noneliminated groups were ...