The synthesis, structural and spectroscopic characterization of monosemiquinone and monocatechol complexes of chromium(III) are described. Compounds of the general form [Cr(N-4)Q](n+), when N-4 represents a tetradentate or bis-bidentate nitrogenous ligand or ligands and Q represents a reduced form of an orthoquinone, have been prepared by two different routes from Cr-III and Cr-II starting materials. The complex [Cr(tren)(3,6-DTBSQ)](PF6)(2), where tren is tris(2-aminoethyl)amine and 3,6-DTBSQ is 3,6-di-tert-butylorthosemiquinone, crystallizes in the monoclinic space group P2(1)/c with a = 11.9560(2) Angstrom, b = 17.0715(4) Angstrom, c = 17.1805(4) Angstrom, beta = 90.167(1)degrees, V = 3506.6(1) Angstrom(3), Z = 4, with R = 0.056 and R-w = 0.070. Alternating C-C bond distances within the quinoidal ligand confirm its semiquinone character. Variable temperature magnetic susceptibility data collected on solid samples of both [Cr(tren)(3,6-DTBSQ)](PF6)(2) and [Cr(tren)(3,6-DTBCat)](PF6) in the range 5-350 K exhibit temperature-independent values of 2.85 +/- 0.1 mu(B) and 3.85 +/- 0.1 mu(B), respectively. These data are consistent with a simple Cr-III-catechol formulation (S = 3/2) in the case of [Cr(tren)(3,6-DTBCat)](PF6) and strong antiferromagnetic coupling (\J\ > 350 cm(-1)) between the Cr-III and the semiquinone radical in [Cr(tren)(3,6-DTBSQ)](PF6)(2). The absorption spectrum of the semiquinone complex exhibits a number of sharp, relatively intense transitions in fluid solution. Group theoretical arguments coupled with a qualitative ligand-field analysis including the effects of Heisenberg spin exchange suggest that several of the observed transitions are a consequence of exchange interactions in both the ground-and excited-state manifolds of the compound. The effect of electron exchange on excited-state dynamics has also been probed through static emission as well as time-resolved emission and absorption spectroscopies. It is suggested that the introduction of exchange coupling and subsequent change in the molecule's electronic structure may contribute to an increase of nearly 3 orders of magnitude in the rate of radiative decay (k(r)), and a factor of ca. 10(7) in the rate of nonradiative decay (k(nr)).