Rational design of graphitic carbon nitride nanostructures (gC(3)N(4)) is vital for various catalytic applications. Herein, we synthesized porous gC(3)N(4) nanotubes (gC(3)N(4)NTs) doped with Pd and Cu (Pd/Cu/gC(3)N(4)NTs) via the consecutive polymerization of melamine in an ethylene glycol solution containing the metal precursors followed by annealing. The gC(3)N(4)NTs, thus produced, possess a well-defined one-dimensional porous nanotube architecture, large surface area (240 m(2) g(-1)), and a homogenous dispersion of Pd and Cu with no need for templates and/or multistep reactions. This merits the CO oxidation activity of Pd/Cu/gC(3)N(4)NTs by 56 degrees C and 96 degrees C higher than that of Pd/gC(3)N(4)NTs and Cu/gC(3)N(4)NTs, respectively. The CO2 reduction activity of Pd/Cu/gC(3)N(4)NTs was a 5.5-fold higher than metal-free gC(3)N(4)NTs. Also, the UV-light irradiation enhanced the CO2 performance of Pd/Cu/gC(3)N(4)NTs by three times. The presented study may pave the way for the utilization of metal-doped gC(3)N(4)NTs in various applications.