The reduction product of dimethylpyrrolidinium cation (DMP(+)) at a lead cathode was isolated and examined in the solid state for the first time. The proposed empirical formula, DMP(Pb-5), was confirmed by elemental analysis, and existence of a cation, DMP(+), and polyatomic Pb anion within the structure was demonstrated. Isolated DMP(Pb-5) is a black solid with metallic conductivity. It shows a weak electron spin resonance signal, but the bulk material is diamagnetic. DMP(Pb-5) is air and temperature sensitive but can be stored for long periods at low temperature and inert atmosphere. Its unique properties are most likely general to all tetraalkylammonium metals.