A homologous series of azomesogens, 4-(4’-n-alkoxy benzoyloxy)-3-chloro phenylazo benzenes of twelve homologues has been synthesized. All the members of the series are either monotropically or enantiotropically nematogenic with threaded texture except first and second member of the series. Smectic mesophase does not occur by any derivatives of the series. Transition temperatures of solid-isotropic or solid-nematic follow zigzag path from first to seven member of the series. Rest of the homologues behaves in abnormal manner. The usual odd-even effect is observed in the nematic-isotropic (or vice versa) transition curve with alternation of transition temperature. Nematic-isotropic transitions do not behave in normal manner from and beyond eighth member of the series. Analytical data support the structure of the molecules. The mesomorphic properties of the series are compared with other structurally related homologous series. Titled homologous series is of middle ordered melting type.