Oxidation of CpCr[(XylNCMe)(2)CH] (Xyl = 2,6-Me2C6H3) with pyridine N-oxide or air generated the mu-oxo dimer, {CpCr[(XylNCMe)(2)CH]}(2)(mu-O). The mu-oxo dimer was converted to paramagnetic Cr(III) CpCr[(XylNCMe)(2)CH](X) complexes (X = OH, O2CPh, Cl, OTs) via protonolysis reactions. The related Cr(III) alkoxide complexes (X = OCMe3, OCMe2Ph) were prepared by salt metathesis and characterized by single crystal X-ray diffraction. The interconversion of the Cr(III) complexes and their reduction back to Cr(II) with Mn powder were monitored using UV-vis spectroscopy. The related CpCr-[(DepNCMe)(2)CH] (Dep = 2,6-Et2C6H3) Cr(II) complex was studied for catalytic oxygen atom transfer reactions with PPh3 using 02 or air. Both Cr(II) complexes reacted with pyridine N-oxide and gamma-terpinene to give the corresponding Cr(III) hydroxide complexes. When CpCr[(DepNCMe)(2)CH] was treated with pyridine N-oxide in benzene in the absence of hydrogen atom donors, a dimeric Cr(III) hydroxide product was isolated and structurally characterized, apparently resulting from intramolecular hydrogen atom abstraction of a secondary benzylic ligand C-H bond followed by intermolecular C-C bond formation. The use of very bulky hexaisopropylterphenyl ligand substituents did not preclude the formation of the analogous mu-oxo dimer, which was characterized by X-ray diffraction. Attempts to develop a chromium-catalyzed intermolecular hydrogen atom transfer process based on these reactions were unsuccessful. The protonolysis and reduction reactions of the mu-oxo dimer were used to improve the previously reported Cr-catalyzed radical cyclization of a bromoacetal.