The mixed-valence compound [Li(THF)(4)]Cu2Br4 was synthesized in a redox reaction from 1,4-dihydroxynaphthalene, CuBr2 and LiNtBuSiMe(3) in THF. X-ray quality crystals of [Li(THF)(4)]Cu2Br4 (monoclinic, P2(1)/c) are obtained from the mother liquor at ambient temperature. In the solid state, infinite chains of anionic [Cu2Br4](-) units are established. These chains are separated by [Li(THF)(4)](+) cations.