Inductively coupled Ar-N2 plasma is characterized by Langmuir probe and optical emission spectroscopy (OES). The plasma parameters including electron temperature, electron number density and electron energy probability functions (EEPFs) are determined by the Langmuir probe for different discharge parameters such as rf power (10–100 W), filling pressure (0.02–0.4 mbar) and argon content (5–95%) in nitrogen discharge. Spectroscopic measurements enable the evaluation of active species concentration ([N],[N2]) in ground electronic state and dissociation fraction. Concentration of active species is increased with the increase in filling pressure in nitrogen discharge keeping argon as an actinometer. It is noticed that the actinometry is an efficient and reliable technique to calculate the concentration of ground electronic state of nitrogen species. Moreover, for different plasma conditions, the molecular dissociation fraction is enhanced, as the Ar content is increased from 5% to 95% in nitrogen discharge. It is found that that dissociation fraction strongly depends on filling pressure and Ar content in nitrogen discharge. Maximum dissociation is observed for 95% Ar at filling pressure of 0.06 mbar. It is also found that the plasma parameters and active species concentration significantly depend on discharge parameters and may be optimized by appropriate selection of discharge conditions.