Reaction of M{N(SiMe3)(2)}(2) (M = Ge, Sn, or Pb) with the sterically encumbered primary phosphine Ar'PH2 (2), Ar' = C6H3-2,6-(C6H3-2,6-Pr-2(i)), at ca. 200 degrees C afforded the highly colored phosphinidene dimers {M(mu-PAr')}(2), M = Ge(3), Sn(4), or Pb(5), with disilylamine elimination. The compounds were characterized by single-crystal X-ray crystallography and heteronuclear NMR spectroscopy. The structures of 3, 4, and 5 featured similar M2P2 ring cores, of which 4 and 5 have 50/50 P atom disorder, consistent with either a planar four-membered M2P2 arrangement with anti aryl groups or with an M2P2 ring folded along the M M axis with syn aryl groups. A syn-folded structure was resolved for the Ge2P2 ring in compound 3. The M P distances resembled those in M(II) phosphido complexes and are consistent with single bonding. The coordination geometries at the phosphorus atoms are pyramidal. DFT calculations on the gas phase models {M(mu-PMe)}(2) (M = Ge, Sn, Pb) agreed with the syn (M-M folded) structural interpretation of the X-ray data. The synthesis of the bulky phosphine Ar'PH2 2 with the use of the aryl transfer agent Ar'MgBr(THF)(2) is also reported. This route afforded a significantly higher yield of product than that which was obtained using LiAr', which tends to result in aryl halide elimination and the observation of insoluble red phosphorus.