High-yield syntheses of the lanthanide dinitrogen complexes [(CpM)(μ-1,2-N)] (, M = Gd, Tb, Dy; Cp = 1,2,4-CBuH), in which the [N] ligands solely adopt the rare end-on or 1,2-bridging mode, are reported. The bulk of the -butyl substituents and the smaller radii of gadolinium, terbium, and dysprosium preclude formation of the side-on dinitrogen bonding mode on steric grounds. Elongation of the nitrogen-nitrogen bond relative to N is observed in , and their Raman spectra show a major absorption consistent with N═N double bonds. Computational analysis of identifies that the local symmetry of the metallocene units lifts the degeneracy of two 5d orbitals, leading to differing overlap with the π* orbitals of [N], a consequence of which is that the dinitrogen ligand occupies a singlet ground state. Magnetic measurements reveal antiferromagnetic exchange in and single-molecule magnet (SMM) behavior in . Ab initio calculations show that the magnetic easy axis in the ground doublets of and align with the {M-N═N-M} connectivity, in contrast to the usual scenario in dysprosium metallocene SMMs, where the axis passes through the cyclopentadienyl ligands. The [N] ligands in allow these compounds to be regarded as two-electron reducing agents, serving as synthons for divalent gadolinium, terbium, and dysprosium. Proof of principle for this concept is obtained in the reactions of with 2,2'-bipyridyl (bipy) to give [CpM(κ-bipy)] (, M = Gd, Tb, Dy), in which the lanthanide is ligated by a bipy radical anion, with strong metal-ligand direct exchange coupling.