2-Pyridinethione (2-mercaptopyridine, H-2mp) undergoes rapid oxidative addition with 2 mol of the 17-electron organometallic radical *Cr(CO)(3)Cp* (where Cp* = C5Me5), yielding hydride H-Cr(CO)(3)Cp* and thiolate (eta(1)-2mp)Cr(CO)(3)Cp*. In a slower secondary reaction, (eta(1)-2mp)Cr(CO)(3)Cp* loses CO generating the N,S-chelate complex (eta(2)-2mp)Cr(CO)(2)Cp* for which the crystal structure is reported. The rate of 2-pyridine thione oxidative addition with Cr-.(CO)(3)Cp* (abbreviated Cr-.) in toluene best fits rate = k(obs)[H-2mp][Cr-.]; k(obs)(288 K) = 22 +/- 4 M-1 s(-1); DeltaH(double dagger) = 4 +/- 1 kcal/mol; DeltaS(double dagger) = -40 +/- 5 cal/mol K. The rate of reaction is the same under CO or Ar, and the reaction of deuterated 2-pyridine thione (D-2mp) shows a negligible (inverse) kinetic isotope effect (k(D)/k(H) = 1.06 +/- 0.10). The rate of decarbonylation of (eta(1)-2mp)Cr(CO)3CP* forming (eta(2)-2mp)Cr(CO)2CP* obeys simple first-order kinetics with k(obs) (288 K) = 3.1 x 10(-4) s(-1), DeltaH(double dagger) = 23 +/- 1 kcal/mol, and DeltaS(double dagger) = +5.0 +/- 2 cal/mol K. Reaction of 4-pyridine thione (4-mercaptopyridine, H-4mp) with Cr-.(CO)(3)Cp* in THF and CH2Cl2 also follows second-order kinetics and is approximately 2-5 times faster than H-2mp in the same solvents. The relatively rapid nature of the thione versus thiol reactions is attributed to differences in the proposed 19-electron intermediate complexes, [(.)(S=C5H4N-H)Cr(CO)(3)Cp*] versus [(.)(H-S-C6H5)Cr(CO)(3)CP*]. In comparison, reactions of pyridyl disulfides occur by a mechanism similar to that followed by aryl disulfides involving direct attack of the sulfur-sulfur bond by the metal radical. Calorimetric data indicate Cr-SR bond strengths for aryl and pyridyl derivatives are similar. The experimental conclusions are supported by B3LYP/6-311+G(3df,2p) calculations, which also provide additional insight into the reaction pathways open to the thione/thiol tautomers. For example, the reaction between H-. radical and the 2-pyridine thione S atom yielding a thionyl radical is exothermic by approximate to30 kcal/mol. In contrast, the thiuranyl radical formed from the addition of H, to the 2-pyridine thiol S atom is predicted to be unstable, eliminating either H-. or HS. without barrier.