A novel azoester homologous series of liquid crystalline (LC) compounds: RO-C6H4-COO-C10H6-N:N-C6H4-OC4H9 (n) without lateral substitution has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC substances with reference to tailed-end group. The novel homologous series consists of 13 homologs (C-1 to C-18) whose nematogenic and smectogenic mesomorphism commences enantiotropically from C-6 and C-12 members of the series, respectively. The C-12-C-18 homologs are smectogenic and C-6-C-18 are nematogenic, of which C-12-C-18 homologs are smectogenic plus nematogenic. The C-1-C-5 homologs are nonmesogenic. Transition temperatures and the textures of the homologs were determined and identified by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren and that of the smectic phase are of the type A or C. Transition curves Cr-M/I, Sm-N and N-I of a phase diagram behaved in normal manner except N-I transition temperature of C-10 homolog which deviated by 9 degrees C-10 degrees C from normal behavior. N-I transition curve exhibited odd-even effect. Analytical, spectral, and thermal data confirms the molecular structures of homologs. Thermal stability for smectic and nematic are 115.5 degrees C and 138.5 degrees C, respectively whose corresponding mesophaselengths are varied from 10.0 degrees C to 16.0 degrees C and 13.0 degrees C to 24.0 degrees C, respectively. Group efficiency order for smectic and nematic are derived fromcomparative study of structurally similar analogous series; as smectic: -OC4H9 (n) > -CH3 > -H; Nematic: -H > -OC4H9 (n) > -CH3