Terminal butoxy ethyl functional groups present in a molecule have their own significance because of their polarity. It has been known that terminally ethyl substituted compounds shows more steady mesophases than do non-substituted mesogenic compounds. Any ethylterminal functionalgroup, which increases the molecular polarizability, without significantly increasing the molecular breadth, increases the thermal stability of the resulting phase transition. Newsynthesized mesogenic homologous series of alkoxy cinnamaldehyde with aminobutoxy ester terminal tail: [2-butoxyethyl -4-3-4 –alkoxy phenyl) acryloyl) oxy) benziledene) amino) benzoate]has been synthesized by condensing an appropriate 4-n-alkoxycinnamaldehydewith butoxyethyl 4-aminobenzoate. The synthesized compounds were characterized by combination of elemental analysis and standard different spectroscopic methods like IR, NMR and DSCThe Phase transition were showed using a optical polarizing microscope. Thin films derivatives were obtained by sandwiching them between a glass slide and cover slip. Twelve members ofthe series were synthesized. All the members Exhibit mesomorphism. Methoxy to tetradecyloxyderiivativeis nematogenic. Butoxy to n- tetradecyloxy derivatives exhibit enantiotropicsmectic Aas well as nematicmesophases. Only hexadecyloxy derivatives exhibit Smectic A phase. The mesomorphic properties of the present series were compared with different structurally related mesogenic homologous series to evaluate the effect of aminobutoxy ethyl tail and alkoxycinnamoyloxy central linkage as well as Schiff’s base unit on phase transition.