A new series of liquid crystals comprising eight heterocyclic isoflavone esters, 7-alkanoyloxy-3-[4'-(3-methylbutyloxyphenyl)]-4H-1-benzopyran-4-ones exhibiting enantiotropic nematic (N) and smectic C (SmC) phases were synthesized and investigated. The mesomorphic properties of all derivatives were investigated by means of differential calorimetry and polarized optical microscopy. Wide angle X-ray diffraction technique was employed to investigate the molecular packing associated with the intermolecular interaction as well as the correlation between the thermal behaviour of these compounds with their anisotropy properties within a mesophase.