Abstract The reactions of dicarbonyl dinitrosyl iron with tri-tert-butylphosphine, di(feri-butyl)-trimethylsilyl-, -germyl-, -stannyl-phosphine, tert-butyl-bis(trimethylsilyl)-, -(germyl)-, -(stannyl)phosphine, as well as with tris(trimethylsilyl)-, -(germyl)-, and -(stannyl)phosphine result in the elimination of one CO ligand and the formation of the corresponding carbonyl dinitrosyl organometalphosphine iron complexes. The IR, 1H, 31P, 13C, and 119Sn NMR spectra of the new complexes are reported and discussed.