With the objective to study the effect of alkoxy terminal chain length on mesomorphic properties of liquid crystals, We have synthesized ester and Schiff base dimers from diamine derivative containing 1,2-dioxyethylene as short spacer with aldehyde derivatives having different lengths of terminal alkoxy chains (n=6-12). The chemical structure of the final products was investigated by fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (H-1 NMR) spectroscopy. The mesomorphic properties and optical textures of the resultant dimers were characterized by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It was found that all the dimers show mesomorphic properties and the increase in terminal alkoxy chain length has pronounced effect on the mesomorphic properties. The temperature range of smectic phase window widens and nematic-isotropic phase window narrows sharply with increasing alkoxy chain length.