Short lifetime has been a thorny problem for chemical and biosensors, and light emitting devices consisting of organic (polymer) materials. In this work, a water-soluble self-doped polyaniline nanocomposite was fabricated by in-situ polymerization of 3-aminophenylboronic acid monomers in the presence of single-stranded DNA dispersed- and functionalized- single-walled carbon nanotubes. For the first time, we found that carbon nanotubes act as novel active stabilizers. This is possibly due to DNA functionalization: they reduced the polyaniline backbone from the unstable, degradable, fully oxidized pernigraniline state to the stable, conducting emeraldine state, which significantly improves the chemical stability of the self-doped polyaniline against the harsh UV irradiation.