Addition of 2 equiv. of the phosphaylide reagents CH2PAr3 (Ar = Ph; 3,5-di-tert-butylphenyl (tBuAr)) to the tetravalent uranium halides, UX4(solvent)n (X = Cl, n = 0; X = Br, solvent = THF, n = 2; X = I, solvent = 1,4-dioxane, n = 2), generates the trans-bis(phosphaylide) adducts UX4(CH2PAr3)2 (Ar = Ph, X = Cl (1Ph-Cl), I (1Ph-I); Ar = tBuAr, X = Cl (2tBu-Cl), Br (2tBu-Br), I (2tBu-I)) in low to good yields. Complexes 1Ph-X exhibit poor solubility in aromatic solvents but are partially soluble in 1,2-difluorobenzene (o-DFB), while 2tBu-X possesses greatly improved solubility in these solvents. The solid-state molecular structures of 1Ph-X·C7H8 and 2tBu-X·n(o-DFB), reveal U-Cylide bonds that range from = 2.506(3)–2.58(1) Å, generally shorter than those found in other uranium-phosphaylide (2.60(1)–2.71(1) Å) and untethered, monodentate U-CNHC (2.62(1)–2.79(1) Å) complexes. Notably, a general contraction of the U-Cylide bond is observed in the UX4(CH2PAr3)2 as the halide series is descended. Attempts to oxidize 2tBu-Cl with Ag+ or Fc+ salts leads to complicated product mixtures from which a few crystals of {[(tBuAr)3PCH2]UCl3(μ-Cl)}2·C7H8 can be isolated, whereas addition of the reductant Cp*2Co to 2tBu-I, in the presence of an extra equiv. of CH2P(tBuAr)3, leads to the formation of the highly encumbered U(III) tris(phosphaylide) adduct UI3[CH2P(tBuAr)3]3 (3tBu-I). Preliminary experiments show these complexes are amenable to substitution reactions as treatment of 2tBu-Cl with 2 equiv. of LiCH2SiMe3 generates the thermally sensitive bis(alkyl) bis(phosphaylide) complex trans-UCl2[CH2P(tBuAr)3]2(CH2SiMe3)2 (4tBu-TMS), a mixed ylide-alkyl system featuring distinct U-Cylide and U-Calkyl σ-bonds. This chemistry demonstrates that untethered, neutral phosphaylide ligands, when coordinated to uranium, are compatible with redox transformations and metathesis reactions. The report of these UX4(CH2PAr3)2 complexes significantly expands the library of known uranium-phosphaylide compounds and contributes to the relatively small collection of uranium complexes featuring neutral C-donor ligands.