Nanophotonics is an exciting new field of science and technology that is directed towards making the smallest possible structures and devices that can manipulate light. Until recently, it was thought that the fundamental laws of diffraction would preclude much further miniaturization of the micron-scale photonic devices we have today. In this presentation, I will show how semiconductor and metallic nanostructures can mold the flow of light in unexpected ways and well below the diffraction limit. As light is bound to play an important role in many chipscale technologies, it is a worthwhile exercise to explore the many opportunities that this newly found ability might bring. In this talk, I will illustrate the use of plasmonic, semiconductor, and dielectric nanostructures in a variety of applications (nanoscale sources, high-speed modulators, and photodetectors). I will also discuss several exciting new hybrid semiconductor/plasmonic devices that capitalize the relative strengths of each of the constituent materials to obtain new functionalities.