As part of a general investigation of low-valent lanthanide phosphido chemistry, the reactions of LnI(2)(thf)(2), LnI(3)(thf)(3), and Ln[N(SiMe(3))(2)](2)(thf)(2) (Ln = Yb, Sm) with KPPh(2) and Ph(2)PH in tetrahydrofuran have been examined. Two different types of lanthanide(II) phosphido complexes of the general formula Ln[PPh(2)](2)(L)(4) with either thf or N-methylimidazole as donor ligands L are reported. The molecular structures show the hexacoordinate lanthanide atoms in slightly distorted octahedral environments with two phosphido ligands in trans positions and slightly pyramidal environments around the phosphorus atoms.