The synthesis and spectroscopic characterization of six bis(acetylido)(phosphino)iron(II) complexes is reported. NMR spectroscopy has been used to determine the geometry of the compounds to be trans with respect to the acetylide ligands. The crystal structures of three iron bis(acetylides) are reported. Crystals of Fe(C = CCH3)2(DMPE)2 (3a) are tetragonal, space group P4n2BAR, with a = 9.1599 (5) angstrom, c = 14.234 (2) angstrom, Z = 2, and R = 0.040 (877 F). Crystals of Fe(C = CPh)2(DEPE)2 (4b) are monoclinic, space group P2(1)/c, with a = 9.783 (2) angstrom, b = 10.675 (2) angstrom, c = 17.855 (3) angstrom, beta = 94.35 (2)-degrees, Z = 2, and R = 0.040 (2195 F). Crystals of Fe(C = CC6H4C = CH)2(DMPE)2 (5a) are monoclinic, space group C2/c, a = 22.017 (5) angstrom, b = 12.366 (2) angstrom, c = 16.952 (4) angstrom, beta = 135.16 (2)-degrees, Z = 4, and R = 0.034 (2026 F).