Poly(ethyl 3-aminophenyl formate), poly(ethyl 3-aminophenyl acetate) and poly(ethyl 3-aminophenyl propionate) were synthesized in 1 M HCl media from respective monomers using ammonium persulphate as oxidizing. The polymers were characterized by FT-IR, UV-vis and H-1-NMR spectroscopy. The effect of electron-withdrawing on the electrical conductivity of polyaniline, was studied. The electron-withdrawing group (ester) bond to the aniline ring affects the formation of charge carriers and electrical conductivity of polymers, therefore, at various bond lengths of the aniline ring, the electron-withdrawing effect decreases and a polymer with electrical conductivity from the semi-conduction order is obtained.