The photoelectroactivity of polycrystalline zinc selenide films prepared by electrochemical codeposition in zinc sulphate solutions of different concentrations containing theI −/I 2 redox couple has been investigated. Measured photopotentials, photocurrents and the initial rate of build-up of photopotentials indicate a significant enhancement in photoelectro-convertibility with increase in concentration, in spite of practically no change in the flat band potentials. The photoelectroactivity of ap-n heterojunction photoelectrochemical cell using cadmium selenide along with zinc selenide has also been studied.