Thermal behaviors were investigated of the binary mixtures of alpha,omega-disubstituted oligothiophenes. Smectic A phase, which is absent in the pure state of each component, was observed in the mixture of dicyano- and dimethylterthiophenes. On the other hand, the mixture of dicyanoterthiophene and terthiophene dicarboxaldhyde did not exhibit a new mesophase. Platelet texture was observed in the mixture of terthiophene dicarboxaldhyde and dimethylterthiophene although the two components did not mix well.