Solar energy has an enormous potential for satisfying the future global energy demand. Organic solar cells are making rapid advances in terms of efficiency, lifetime, and technology and have a true promise to become a source of renewable energy. They present fascinating opportunities for scientific research and technological development. The lecture will give provide an introduction to organic solar cells and discuss how new organic semiconductors with extended optical absorption and high mobilities for charges can further enhance the performance. The effect of the morphology of the active layer on the generation, separation, and collection of photogenerated charge carriers will be highlighted. A substantial gain in performance can further be realized with multi-junction solar cells where two or more absorber layers reduce thermalization and transmission losses. Finally, first steps to store solar energy in chemical bonds will be presented using novel organic photoelectrochemical cells that split water and produce hydrogen.