A series of dialkylterthiophenes, CH3(CH2)(n)-TTh-(CH2)(n),CH3 (TTh=terthiophene, n=3,5,7,9,11) were synthesized and characterized. All the dialkyl-substituted terthiophenes display smectic mesophase except dibutylterthiophene exhibiting only a crystal melting. The thermal stability of the mesophase of dialkylterthiophene increases with increasing the length of alkyl chains. The complexation of the dialkyl terthiophenes with Cp*Ru suppresses liquid crystallity and all the complexes becomes amorphous.