For more than two decades, scientists and engineers have focused on impending limitations (from high-power densities and heat distribution to device patterning) that constrain the future miniaturization of conventional silicon technology. Thus far, academic and industrial efforts have risen to the challenge and continue to advance planar silicon processing, pushing traditional microtechnology to the nanometer scale. However, insurmountable limitations, both of physical nature and cost, still loom and motivate the research of new nanomaterials and technologies that have the potential to replace and/or enhance conventional silicon systems. As time has progressed, another Group IV element has emerged as a front-runner, looking beyond silicon, in the form of carbon-based nanotechnology. The focus of this issue is to provide a comprehensive look at the state-of-the-art in carbon-based nanomaterials and nanotechnologies and their potential impact on conventional silicon technologies, which are not limited to electronics but also encompass micro- and nanoelectromechanical systems, optoelectronics, and memory. Recent advances in carbon nanotube growth, sorting, and optoelectronics will be discussed, and the relatively new and surging area of graphene research will be introduced. In addition, progress in controlling the growth and properties of ultrananocrystalline and nanocrystalline diamond thin films will be reviewed. These efforts are multidisciplinary heavily materials focused, and tend to translate information and ideas to other carbon-based studies (e.g., graphene is the building block of carbon nanotubes).