Mixtures of Ln(SC6F5)(3) and Ln(EPh)(3) (E = S, Se) react with elemental E to give chalcogen-rich clusters with fluorinated thiolate ancillary ligands. The structures of both (THF)(6)Yb4S(SS)(4)(SC6F5)(2) and (THF)(6)Yb4Se(SeSe)(4)(SC6F5)(2) have been established by low-temperature single-crystal X-ray diffraction, Both compounds contain a square array of Yb(III) ions connected by a central mu(4)-E2- ligand. The edges of the square Yb-4 array are bridged by four mu(2)(EE) ligands, and two terminal SC6F5 are on the same side of the Ln(4) plane that is capped by the mu(4)-E2- ion, Redox inactive (THF)(6)Tpn(4)Se(SeSe)(4)(SC6F5)(2) was also prepared to establish the extension of this chemistry to the redox inactive Ln. These clusters are soluble in toluene.