A series of lanthanide complexes bearing organic radical ligands, [Ln(Cp-R)(2)(bipy center dot(-))] [Ln = La, Cp-R = Cp-tt (1); Ln = Ce, Cp-R = Cp-tt (2); Ln = Ce, Cp-R = Cp" (3); Ln = Ce, Cp-R = Cp"' (4)] [Cp-tt = {(C5H3Bu2)-Bu-t-1,3}(-); Cp" = {C5H3(SiMe3)(2)-1,3}(-); Cp"' = {C5H2(SiMe3)(3)-1,2,4}(-); bipy = 2,2'-bipyridyl], were prepared by reduction of [Ln(Cp-R)(2)(mu-I)](2) or [Ce(Cp'")(2)(I) (THF)] with KC8 in the presence of bipy (THF = tetrahydrofuran). Complexes 1-4 were thoroughly characterized by structural, spectroscopic, and computational methods, together with magnetism and cyclic voltammetry, to define an unambiguous Ln(III)/bipy center dot(-).radical formulation. These complexes can act as selective reducing agents; for example, the reaction of 3 with benzophenone gives [{Ce(Cp")(2)(bipy)}(2){k(2)-O,O'-OPhC(C6H5)CPh2O}] (7), a rare example of a "head-to-tail" coupling product. We estimate the intramolecular exchange coupling for 2-4 using multiconfigurational and spin Hamiltonian methods and find that the commonly used Lines-type isotropic exchange is not appropriate, even for single 4f e(-)/organic radical pairs.