A spectroscopic and computational study of a series of 2,5-bis(2-thien-2-ylethenyl) thiophene-based oligomers with a para-R-arylethenyl substituent is reported. The primary aim of this investigation is to increase understanding of how charge moves through these mols. by comparing the neutral and oxidized structures for each mol. To this end, the B3LYP/6-31G(d) computational method was used to calc. the geometry and vibrational spectra for all mols. considered and their oxidn. products. For vibrational data, mean abs. deviations for frequencies between exptl. and theor. results ranging from 2 to 18 cm-1 were obtained. Exptl. Raman spectroscopy, in conjunction with calcd. bond length analyses, was used to gain an insight into the position and delocalization of the charged defect on the oxidized oligomers. The relative frequencies of different ethylene stretching modes served as a particularly useful probe in this regard. It was found that the ethenyl spacers do not impede p-electron delocalization and, therefore, give rise to a longer conjugation length relative to the corresponding terthiophenes. Furthermore, the para-R-arylethenyl substituent was found to orient the charged defect toward a specific region of the 2,5-bis(2-thien-2-ylethenyl)thiophene conjugation path.