The principal objectives of this chapter are to demonstrate the principal physical approaches to create highly efficient heterostructured photoactive compositions of two types: semiconductor-semiconductor and semiconductor-metals. The introduction briefly reviews the development of photoactive materials that transit toward heterostructured systems, gives a description of the key photoprocesses in a single component photoactive material, which plays a significant role in semiconductors as a component of heterostructures, describes key parameters that control their impact in functionality of heterostructured materials, and finally presents various scenarios of charge transfer in selectively photoexcited heterostructured materials of both types. Particular attention is given to the formation of heterojunctions and key parameters that determine both optical and electronic properties of heterostructured materials. A more profound knowledge and understanding of those key steps that take place in heterostructures and, particularly, at the heterojunctions, together with factors that determine the dominating charge transfer pathways in such materials, are essential for further development of highly photoactive heterostructured compositions and their application to solar energy conversion processes.