Semiconductor nanocrystals have emerged as promising materials for light harvesting and production of electrical energy. Their unique optical properties and solution processibility suggest that they can be utilized in new ways to build on the knowledge base existing from the study of bulk semiconductors. Here, CuInSe2, CdTe, and CdSe are discussed. Synthetic control of size, shape, crystal structure, and elemental composition are crucial to realizing the potential of these nanoscale building blocks. In this work, new methods for colloidal synthesis of semiconducting nanocrystals are presented. As a consequence, the improved control over structure makes it possible to self-assemble them into oriented and multicomponent films. This provides a route for the future to pattern nanoscale structure into solar cell active layers from the bottom up.