The ease of reduction of pi-conjugated poly(p-phenylene)-, poly(naphthalene-2,6-diyl) -, and poly(naphthalene-l,4-diyl)-type polymers is determined by the electron accepting properties of the recurring aromatic units. Linear relationships hold between reduction potentials (E(red)) Of the pi-conjugated poly(arylene)s and electron affinities (EA) of the recurring arylene units : E(red) = rho EA + a. A rho value of 0.85 +/- 0.02 is found for the three types of polymers investigated.