Dinitrogen activation by titanium benzene complex has been studied by matrix isolation infrared spectroscopy and density functional theoretical calculations. The ground state titanium atoms react with dinitrogen and benzene mixtures in solid argon to form the end-on bonded Ti(eta(6) -C6H6)(eta(1)-NN) and Ti(eta(6)-C6H6)(eta(1)-NN)(2) complexes spontaneously on annealing. These complexes rearrange to the side-on bonded Ti(eta 6-C6H6)(eta(2)-N-2) and Ti(eta(6)-C6H6)(eta(1)-NN)(eta(2)-N-2) molecules with a more activated N-2 upon red light irradiation. (c) 2006 Elsevier B.V. All rights reserved.