This paper reports the conductivities of polyphenylquinoxaline (PPQ) doped with aqueous H2SO4. The highest conductivity of doped PPQ is 4.5 x 10(-2) S cm-1 obtained by the four-probe method at room temperature. The influence of concentration of aq. H2SO4, and doping time on the conductivity of doped PPQ is discussed. The structures of doped and undoped PPQ were confirmed by Fourier-transform infra-red, ultra-violet and X-ray photoelectron spectroscopies, electron spin resonance and elemental analysis. Also, the stability of the conductivity value was examined.