New three and four rings containing liquid crystalline 3,5-disubstituted 1,2,4-oxadiazoles with 4-substituted phenyl, cyclohexyl, biphenyl and phenylcyclohexyl substituents have been synthesized. It was shown that structure and nature of the cyclic fragments, position of the strong polar (NO2) or weak polar (Alk, AlkO, Hal) groups in respect to the heterocyclic unit significantly effect on the temperature and dielectric properties of the new mesogens.