Uranium mono(imido) species have been prepared via the oxidation of Cp*U((PDIMe)-P-Mes)(THF) (1-Cp*) and [(CpU)-U-P((PDIMe)-P-Mes)](2) (1-CpP), where Cp* = eta(5)-1,2,3,4,5-pentamethylcyclopentadienide, Cp-P = 1-(7,7-dimethylbenzyl)cyclopentadienide, (PDIMe)-P-Mes = 2,6-[(Mes)N-CMe](2)C5H3N, and Mes = 2,4,6-trimethylphenyl, with organoazides. Treating either with N3DIPP (DIPP = 2,6-diisopropylphenyl) formed uranium(IV) mono(imido) complexes, (CpU)-U-P(NDIPP)((PDIMe)-P-Mes) (2-Cp-P) and Cp*U-(NDIPP)((PDIMe)-P-Mes) (2-Cp*), featuring reduced [(PDIMe)-P-Mes](-). The addition of electron-donating 1-azidoadamantane (N(3)Ad) to 1-Cp* generated a dimeric product, [Cp*U(NAd)((HPDIMe)-H-Mes)](2) (3), from radical coupling at the p-pyridine position of the pyridine(diimine) ligand and H-atom abstraction, formed through a monomeric intermediate that was observed in solution but could not be isolated. To support this, Cp*U(Bu-t-(PDIMe)-P-Mes)(THF) (1-Bu-t), which has a tert-butyl group protecting the para position, was also treated with N(3)Ad, and the monomeric product, Cp*U(NAd)(Bu-t-(PDIMe)-P-Mes) (2-Bu-t), was isolated. All isolated complexes were analyzed spectroscopically and structurally, and the dynamic solution behavior was examined using electronic absorption spectroscopy.