The reaction of 1a and 0.5 equiv. [Ni(CO)Cp]2 in benzene or toluene results in a colour change from red to yellow after one hour stirring at 25 ºC (Scheme 1). Monitoring the reaction by 1 H NMR spectroscopy revealed slow consumption of 1a with concomitant formation of a series of broad resonances in the range +10 to -10 ppm, suggestive of formation of a paramagnetic species (see Figure ). Pale yellow crystals of the product 2 were obtained from recrystallization of the crude mixture from diethyl ether at -35 ºC. X-ray diffraction of single crystals confirmed the structure of complex 2, derived from dissociation of the [Ni(CO)Cp]2 dimer and coordination of the zinc-hydride bond of 1a to the resultant monomer (Figure ). The Ni---Zn distance of 2 is 2.326(1) Å. The hydride ligand was located in the Fourier difference map and refined freely. The Zn-H and Ni-H distances are 1.92(6) and 1.50(8) Å. The Zn-Ni-CO angle is 82.7(2)º. The Zn-H bond is close to perpendicular to the Ni-CO vector with the H-Ni-C-O torsion angle being 85º. This geometry, along with key bond lengths, are retained in DFT optimised structures (BP86-GD3), suggesting the Zn-H unit has a preferred orientation which is orthogonal to the CO ligand.