The liquid crystallinity of poly(3-dodecylthiophene) was studied systematically at selected temperatures with manually controlled shearing, using optical microscopy and differential scanning calorimetry, to determine the necessary conditions for the formation of liquid crystallinity. Poly(3-dodecylthiophene) did not show thermotropic liquid crystalline behavior under conditions which are usually used in the study of thermotropic liquid crystallinity. When a shear stress was applied to a solvent cast film, a Schileren texture was observedin situ. A finer texture was observed as the annealing temperature and time of the sample film were increased. There was no direct relationship between the melting behaviors in differential scanning calorimeter thermograms and the liquid crystalline behavior of poly(3-dodecylthiophene).