We present a systematic investigation of the structural and electronic changes that occur in an Fe(0)-N-2 unit (Fe(depe)(2)(N-2); depe = 1,2-bis(diethylphosphino)ethane) upon the addition of exogenous Lewis acids. Addition of neutral boranes, alkali metal cations, and an Fe2+ complex increases the N-N bond activation (Delta nu(NN) up to 172 cm(-1)), decreases the Fe(0)-N-2 redox potential, polarizes the N-N bond, and enables -N protonation at uncommonly anodic potentials. These effects were rationalized using combined experimental and theoretical studies.