The invention provides a fast, scalable, room temperature process for fabricating metallic nanorods from nanoparticles or fabricating metallic or semiconducting nanorods from carbon nanotubes suspended in an aqueous solution. The assembled nanorods are suitable for use as nanoscale interconnects in CMOS-based devices and sensors. Metallic nanoparticles or carbon nanotubes are assembled into lithographically patterned vias by applying an external electric field. Since the dimensions of nanorods are controlled by the dimensions of vias, the nanorod dimensions can be scaled down to the low nanometer range. The aqueous assembly process is environmentally friendly and can be used to make nanorods using different types of metallic particles as well as semiconducting and metallic nanotubes.