Careful control of the coordination environment about a group 4 metallocene (M = Zr, Hf) allows synthesis of strongly activated, side-on bound N2 complexes that are best described as having four electron reduced diazenido cores. Addition of another relatively inert amospheric gas, CO2, resulted in carboxylation of the N2 ligand. The regiochemistry of the carboxylation reaction can be controled by the symmetry of the metallocene complex. Treatment with appropriate electrophiles furnished the corresponding free hydrazines, constituting the synthesis of various organic hydrazines from N2 and CO2. This topic, along with the synthesis of new zirconium dinitrogen complexes and their reactivity, will be presented.