Electroactive molecules and molecular nanostructures are explored intensively as new alternative materials for electronic applications. Among the most promising systems for molecular electronics, the single-wall carbon nanotubes (CNs) are particularly interesting. These long cylindrical nanostructures involve covalent bonds, which make them exceptionally strong. Moreover, they offer excellent conduction and high current carrying capabilities. I will quickly review their electrical properties and show the recent progress for building carbon nanotube field-effect transistors (CNFETs). We will also present physical and chemical phenomena occurring at the metal-nanotube junctions. Finally, I will present the smallest light source based on a CNFET with an emission wavelength in the near IR region.