Electrocrystallization of bis(ethylenedithio)tetrathiafulvalene, BEDT-TTF, in the presence of bis(tetrabutylammonium)platinum(II) bis(1,2-dithiosquarate) affords a new radical-ion salt of 2:1 stoichiometry. The crystal structure consists of a mixed stack, made of organic (BEDT-TTF.+)(2) dimers separated by [Pt-II(S2C4O2)(2)](2-) anions along the b axis of the unit cell. The compound is one of the few reported examples of the simplest system for CT organic conducting materials, i.e. a dimer of two open shell conjugated molecules interacting through their pi-electron systems.