The title compound, bis(1,2-diphenyl-2-sulfanylideneethanethiolato-kappa S-2,S')-(1,3,5-triaza-7-phosphaadamantane-kappa P)cobalt(II) dichloromethane hemisolvate, [Co(pdt)(2)(PTA)]center dot 0.5C(2)H(4)Cl(2) or [Co(C14H10S2)(2)(C6H12N3P)]center dot 0.5C(2)H(4)Cl(2), contains two phenyldithiolene (pdt) ligands and a 1,3,5-triaza-7-phosphaadamantane (PTA) ligand bound to cobalt with the solvent 1,2-dichloroethane molecule located on an inversion center. The cobalt core exhibits an approximately square-pyramidal geometry with partially reduced thienyl radical monoanionic ligands. The supramolecular network is consolidated by hydrogenbonding interactions primarily with nitrogen, sulfur and chlorine atoms, as well as parallel displaced pi-stacking of the aryl rings. The UV-vis, IR, and CV data are also consistent with monoanionic dithiolene ligands and an overall CoII oxidation state.