Poly-N-(3,6-dioxaheptyl)aniline (poly-NDHAn), containing two oxyethylene units in the side chain, was prepared electrochemically to improve electrochemical redox activity of polyaniline. The cyclic voltammogram of poly-NDHAn showed a reversible redox peak around 0.6 V (vs. SCE) and another irreversible redox couple at -1.2 V and -0.1 V in acetonitrile solution containing LiClO4. The latter couple was attributed to the n-type doping and undoping reactions. Poly-NDHAn unlike polyanilines had an absorption maximum in the visible region even in its neutral form. The molecular weight of poly-NDHAn was high (1,200,000), and the conductivity value was 1 x 10(-3) Scm(-1). The effect of polymerizing conditions on the conductivity of poly-N-heptylaniline was also studied. Poly-N-heptylaniline with a higher conductivity was obtained by constant potential polymerization at 1.2 V in acetonitrile solution containing H2SO4.