Reported N-2 complexes of cobalt do not have substantial weakening of the N-N bond. Using diketiminate ligands to enforce three-coordinate geometries, we have synthesized several novel CoNNCo complexes. In formally univalent complexes, cobalt is poorer than iron at weakening the N-N bond, but in formally zerovalent complexes, cobalt and iron give similar N-N weakening. The weakening is due to cobalt-to-N-2 pi-backbonding, and potassium cations pull more electron density into N-2. These results show that the low coordination number of a trigonal-ptanar geometry is impetus enough to make even the etectronegative cobalt weaken the N-N bond of N-2.