The amazing physical properties of carbon nanotubes and their derivatives have opened up a wide range of technological uses. The field of carbon nanotube (CNT) semiconductor metal oxide (SMO) nanocomposites and inorganic hybrid carbon-based nanostructures has grown significantly over the last 10 years, resulting in the creation of new functional features. However, a number of CNT parameters, such as form, size, interaction dispersion, alignment, purity, aspect ratio, and the volume percentage of nanotubes of nanotubes, have a significant impact on the properties of composites. In order to acquire reproducible electrical, physical, and mechanical properties, all of which are crucial for device applications, all of these factors can be regulated by selecting an appropriate synthesis technique. This chapter will therefore go into great length about the synthesis of different carbon-based nanocomposites, such as carbon nanotubes, carbon dots, carbon quantum dots, nanodiamonds (NDs), graphene, graphene oxide (GO), reduced graphene oxide (rGO), carbon black, fullerenes, and carbon fibers (CFs), as well as their benefits in reducing air pollution.