The photovoltaic properties of thin films and double-layer heterostructures made of sulphonamide-substituted zinc phthalocyanine were studied. The films of phthalocyanine were prepared from a chloroform solution by spin-coating. Top-layer components of heterostructures (pentacene, lead phthalocyanine, perylene derivative) were thermally evaporated on phthalocyanine films. The effect of annealing and aging on the photovoltaic properties of films was examined. The observed reversal of the sign of photovoltage spectra for the films and heterostructures was explained in present paper.