In this work, the structural and optoelectronic properties of C66H54Br6N6O12 nanotubes, which is in the triclinic phase, have been studied by the Perdew- Burke- Ernzrhof Generalized Gradient Approximation (PBE- GGA). The semi metallic behaviors and the flat bands are observed in the band structure with 2.06 eV band gap. From the optical spectra, this nanotube is birefringence with Plasmon energies of 23.41, 23.36 and 23.55 eV at x, y and z direction, respectively. Cauchy coefficients have been obtained in the wavelength range of 550 to 850 nm. The results show that this nanotube cab be used in the optoelectronic devices like metallic carbon nanotube and glasses.