In conclusion, we have shown an organometallic diiron complex in which an Fe-Fe bond connects a high-spin iron(II) site and a low-spin iron(0) site. This may be described as a CpFe(CO)2 -fragment acting as an X-type ligand toward the diketiminate-Fe fragment, using the MLX notation of Green. Despite the short Fe-Fe distance (2.41 Å), the bond order of 0.5 implies limited covalent interaction and significant electrostatic interaction between the metals. Using the accumulated 57 Fe Mössbauer database of diketiminate-Fe compounds, the CpFe(CO)2 "metalloligand" can be classified as more donating than halides or O/N ligands, but not as soft as most alkyl ligands. In the future, this method could be used to design systems with precisely tuned metalloligands.