New homologous series with -COO- and -N=N- as central group have been synthesized by the treatment of 4-n-alkoxy benzoyl chloride with 2-Hydroxy - naphthyl – 1 – azo – 4’ – nitro benzene. All the homologues of the series are enantiotropically nematogenic without exhibition of smectic mesophase. The texture of nematic mesophase is of threaded type. Well known odd-even effect is clearly observed in the nematic isotropic transition curve. Thermal stabilities and liquid crystalline properties are compared with other structurally identical homologous series. Transition temperatures are observed through hot stage polarizing microscope. Analytical data support the structure of molecules.