We used a combinatorial chemistry approach to develop the molecular plastic solar cells based on soluble fullerene derivatives or solubilized TCNQ molecules in combination with conjugated polymers. Profiles, formed by the diffusion of low molecular weight component in the spin-cast polymer host were used. The ratio between low molecular weight acceptor and polymer changed along the diffusion gradient direction from 100% to 0% at the distances 10-20 mm. Optical and electrophysical properties such as absorption, luminescence, short circuit current and open circuit voltage were measured using a specially designed installation with the resolution of 25 points per millimetre.