Two series of bent shaped 1,3,4-oxadiazole/thiadiazole heterocyclic ring containing liquid crystalline (LC) compounds were synthesized and characterized by FT-IR, $^{1}_{}$H, $^{13}_{}$C-NMR and ESI-Mass spectro-scopic techniques. Liquid crystal properties were investigated by polarized optical microscopy and differential scanning calorimetry. All the compounds exhibited mesophases such as nematic, smectic A and smectic C phases. The liquid crystalline effects were ascertained by changing the central atom in the heterocyclic ring and by increasing the length of the terminal alkyloxy chains which bring considerable improvements on the mesomorphic properties. The absorption and emission spectral studies of all the compounds were investigated and confirmed.