We studied the dynamic behavior of director-reorientation induced by linearly polarized light in an oligothiophene-doped liquid crystal (LC) by transmission-mode analyses and the Z-scan measurement. An in-plane reorientation process occurred and LC molecules tended to reorient parallel to the polarization of incident light in the case of low-intensity irradiation. The thermal effect due to absorption affects the reorientation behavior largely in the case of high-intensity irradiation.