Very strong reducing power [1] and a marked inclination toward performing cooperative attack on the same substrate [2] are the basis of the distinctive reactivity of divalent f-block metals. [3] In spite of the great interest in this field, divalent actinides remain basically unknown, possibly as a result of an intrinsic instability of this oxidation state. Moreover, the significance of the low oxidation states remains questionable, since the f electrons are expected to be more likely engaged in backbonding with the ligand rather than being metal-centered, nonbonding electrons. As a consequence, even simple salts such as UI 2 [4] and ThI 2[5] are regarded as divalent only from the point of view of formula, since the f electrons are believed to be located in a type of conduction band. Nevertheless, the electron-rich nature of these species raises expectations for high reactivity and strong reducing power. This idea is substantiated by the chemical behavior of the two known U II synthons, [6] and by some recent findings that a trivalent calix-tetrapyrrolide uranium compound resulted, upon reduction, in a complex series of transformations including dinitrogen cleavage, solvent deoxygenation, and depolymerization of silicone grease. [7] For thorium such chemistry is limited to a handful of trivalent compounds or synthons. [8] Given this scenario, we became interested in exploring the chemistry of divalent Th complexes, most likely synthons, with the dual purpose of: 1) probing the stability of an oxidation state unknown for thorium and 2) preparing potent two-electron reductants for further reactivity studies. For this purpose, we focused on pyrrole-based polyanions as ligands. These species have proved their ability both to stabilize low oxidation states in large cluster structures [9] and to increase the high reactivity of the low-valent compounds even further. [3f-n] Here we describe the reduction of a tetravalent polypyrrolide thorium complex, which resulted in both solvent fragmentation and formation of the first divalent synthon thorium arene complex.The reactions