In this paper the deposition of polymeric nitrogenated amorphous carbon (a-C:H:N) films from a mixture of hydrogen, methane and nitrogen, using the electron cyclotron resonance chemical vapor deposition (ECR-CVD) system is reported. Rutherford backscattering spectroscopy (RBS) and elastic recoil detection analysis (ERDA) measurements were used to determine the actual amount of nitrogen, carbon and hydrogen in the films. The results showed that there is insignificant change in the atomic concentration of C but a slight decrease in the atomic concentration of H with increasing N incorporation. A slight decrease in the amount of bonded H and an increase in the C=N bond was also observed as deduced from infrared (IR) absorption measurements. The optical gap was found to decrease and the Urbach band tail width increase at larger N-2 flow ratio. The conductivity increased by three orders of magnitude compared to that of films prepared in the absence of N-2. The results suggest that the observed C=N double bond effectively bridges the aromatic rings resulting in a delocalization of carriers.