A new 3 Π– 3 Σ band was observed in a discharge plasma of the nitrogen molecule and helium using near-infrared diode laser kinetic spectroscopy. All the lines in this band exhibited line broadening of more than 0.1cm −1 . Rotational analysis revealed that the lower state of the transition was the E3Σg+(v=0) state of N 2 , which had already been studied in the D 3 Σ–E 3 Σ band. The term value and rotational constant suggested that the upper state is the G 3 Π u Rydberg state with an electron configuration of (N 2 + :X 2 Σ core)(3pπ u ). The line broadening is attributed to predissociation through a homogeneous interaction with a repulsive Π u state.