Among many outstanding properties of carbon-based interconnects, it is of great interest for nanoelectronics applications the possibility to have an electrical resistance almost insensitive or even decreasing with temperature increase. This behavior has been theoretically predicted and experimentally proven for carbon nanotubes and graphene nanoribbons, but only in controlled conditions, and for limited ranges of geometrical dimensions and temperature. This paper demonstrates the possibility of observing such a desirable behavior in large dimension carbon nanotubes and graphene conductors, made by self-assembly of short tubes and graphene flakes, respectively. The electro-thermal characterization of a 150μm-long carbon conductor clearly shows the possibility of having a negative temperature coefficient of the resistance. © 2016 IEEE.