The structures of oligothienyls (T4-T6) has been evinced from x-ray powder diffraction data using the Rietveld full-profile analysis on particularly pure samples , we were able to overcome preferred orientation effects. Both T4 and T6 molecules display no internal symmetry, are planar within 10-degrees and present a herringbone arrangement, the angle between mean planes of adjacent molecules ranges from 70-degrees(T4) to 60-degrees(T6). Intra and intermolecular energy minimization is in progress.