A series of uranyl compounds with the redox-active iminoquinone ligand have been synthesized, and their electronic structures elucidated using multinuclear NMR, EPR, electronic absorption spectroscopies, SQUID magnetometry, and X-ray crystallography. Characterization and analysis of the iminoquinone (iq(0)) complex, ((dipp)iq)UO2(OTf)(2)THF (1-iq), the iminosemiquinone (isq(1-)) complex, ((dipp)isq)(2)UO2THF (2-isq), and the amidophenolate (ape(2-)) complex, [(d(ipp)ap)(2)UO2THF][K(18-crown-6)(THF)(2)](2)(3-ap crown) show that reduction events are ligand-based, with the uranium center remaining in the hexavalent state. Reactivity of 2-isq with B-chlorocatecholborane or pivaloyl chloride leads to U-O-uranyl bond scission and reduction of U(VI) to U(IV) concomitant with ligand oxidation along with organic byproducts. O-18 isotopic labeling experiments along with IR spectroscopy, mass spectrometry, and multinuclear NMR spectroscopy confirm that the organic byproducts contain oxygen atoms which originate from U-O-uranyl bond activation.