The 1,3-disphosphete complex [CpBnCo(η4-P2C2tBu2)] (1) is prepared from the reaction of the sterically demanding [CpBnCo]n (CpBn=C5(CH2C6H5)5) with tert-butyl phosphaalkyne (tBu−C≡P). The reaction of 1 with copper halides CuX (X=Cl, Br, I) leads to the formation of one-dimensional coordination polymers of the general formula [{(CpBnCo)(μ3,η4 : 1 : 1-(PCtBu)2)}{Cu(μ-X)}2(MeCN)]n (X=Cl (2), Br (3), I (4)). All compounds are studied in solution by multinuclear NMR spectroscopy and mass spectrometry and in the solid state, by single crystal X-ray diffraction and 31P{1H} MAS NMR.