We derive a new relation between the metallicity of Seyfert 2 Active Galactic Nuclei ( AGNs ) and the intensity of the narrow emission-lines ratio N 2 O 2 =log ( [ N ii ] \lambda 6584/ [ O ii ] \lambda 3727 ) .
The calibration of this relation was performed determining the metallicity ( Z ) of a sample of 58 AGNs through a diagram containing the observational data and the results of a grid of photoionization models obtained with the Cloudy code .
We find the new Z / Z _ { \odot } - N 2 O 2 relation using the obtained metallicity values and the corresponding observational emission line intensities for each object of the sample .
Estimations derived through the use of this new calibration indicate that narrow line regions of Seyfert 2 galaxies exhibit a large range of metallicities ( 0.3 \ > \la \ > Z / Z _ { \odot } \ > \la \ > 2.0 ) , with a median value Z \approx Z _ { \odot } .
Regarding the possible existence of correlations between the luminosity L ( H \beta ) , the electron density , and the color excess E ( B - V ) with the metallicity in this kind of objects , we do not find correlations between them .