Reaction of diphenylphosphinocyclopentadiene with Yb (C6F5)2 or with ytterbium metal and Hg(C6F5)2 in tetrahydrofuran (thf) gives, after workup with toluene, the phosphinoytter-bocene, [Yb (C5H4PPh2)2(thf)]. Treatment with thf or with N, N, N′, N′- tetramethylethane-1, 2-diamine (tmen) yields [Yb (C5H4PPh2)2L2] (L = thf or L2 = tmen). Redox trans- metallation between ytterbium metal and Tl (C5H4PPh2) in l, 2-dimethoxyethane (dme) gives thallium metal and [Yb (C5H4PPh2)2(dme)]. The ytterbium-transition metal hetero-bimetallics [Yb (thf) (C2H4PPh2)2Z]. nPhMe [Z = Ni(CO)2, Mo(CO)4 or PtMe2, n = 2/3 or 1] have been prepared by reaction of [Yb (thf)(C5H4PPh2)2] with Ni(CO)2(PPh3)2, Mo(CO)4(nbd) (nbd = norbornadiene) or PtMe2(cod) (cod = cycloocta-1, 5-diene) in toluene. Treatment of the heterobimetallics with tetrahydrofuran [Z = PtMe2 or Mo(CO)4] or a preparation in thf /toluene [Z = Ni(CO)2] yields [Yb (thf)2(C5H4PPh2)2PtMe2]. thf, [Yb (thf)2(C2H4PPh2)2Mo(CO)4]. thf and [Yb (thf)2 (C5H4PPh2)2Ni(CO)2]. The X-ray crystal structure of the last compound (triclinic, space group Pi, a 14.514(5), b 13.565(1), c 10.866(5) 93.11(2), β 104.65(3), γ 97.25(2)°, U 2045 Å 3, Z 2, 5141 data refined to R 0.031) reveals eight-coordinate ytterbium with a pseudo-tetrahedral arrangement of two thf ligands and the cyclopentadienyl ring centroids of two ή 5-diphenylphosphinocyclopentadienide ligands. The latter are also bonded through phosphorus to the Ni(CO)2 group, resulting in tetrahedral stereochemistry for nickel. Infrared spectroscopy suggests the presence of ytterbium- isocarbonyl bonding in solid [Yb (thf)(C2H4PPh2)2Z] [Z = Ni(CO)2 or Mo(CO)4].