Seventeen homologs of chiral 6-phenyl-1,2,4-triazines were synthesized and their mesomorphic properties were evaluated with a DSC and a polarizing microscope. It is found that compounds in this series show a strong tendency to generate the chiral smectic C (Sc*) phase which exists in a wide temperature range from about 30-degrees-C to 90-degrees-C. By comparing the thermal stability of the mesophase (smectic phase) of triazine derivative with that of analogous 5-phenylpyrimidine and 2-phenylpyridazine derivatives, it is clear that the dipole moment perpendicular to the molecule of the core part plays an important role in the thermal stability of the mesophase (smectic phase). Moreover, the electro-optical properties for some compounds were also measured and the results indicate that the switching times (tau’s) are relatively fast, though the spontaneous polarizations (Ps’s) are very small.