A full-organic donor/acceptor (DA) network formed by crystalline molecules is introduced to organic solar cells. Structural analysis shows that the network is composed of donor and acceptor nanocrystals. The increased DA interface area increases photo current generation and the interconnected networks form conductive pathways for charge extraction. The solar cell using nanocrystalline DA network shows a three-fold improvement on photocurrent over that of a bilayer cell using the same DA combination.