Measurement of state-of-charge of lead-acid batteries using potentiometric sensors would be convenient; however, most of the electrochemical couples are either soluble or are unstable in the battery electrolyte. This paper describes the results of an investigation of poly (divinylferrocene) (PDVF) and Poly(diethynylanthraquinone) (PAQ) couples in sulfuric acid with the view to developing a potentiometric sensor for lead-acid batteries. These compounds were both found to be quite stable and undergo reversible reduction/oxidation in sulfuric acid media. Their redox potential difference varied linearly with sulfuric acid concentration in the range of 1 M - 5 M (i.e. simulated lead-acid electrolyte during battery charge/discharge cycles). A sensor based on these compounds has been investigated.