Research on the one-electron reduced analogue of NO, namely nitroxyl (HNO/NO ), has revealed distinguishing properties regarding its utility as a therapeutic. However, the fleeting nature of HNO requires the design of donor molecules. Metal nitrosyl (MNO) complexes could serve as potential HNO donors. The synthesis, spectroscopic/structural characterization, and HNO donor properties of a {CoNO}(8) complex in a pyrrole/imine ligand frame are reported. The {CoNO}(8) complex [Co(LN4PhCl)(NO)] (1) does not react with established HNO targets such as FeIII hemes or Ph3P. However, in the presence of stoichiometric H+ 1 behaves as an HNO donor. Complex 1 readily reacts with [Fe(TPP)Cl] or Ph3P to afford the {FeNO}(7) porphyrin or Ph3P=O/Ph3P=NH, respectively. In the absence of an HNO target, the {Co(NO)(2)}(10) dinitrosyl (3) is the end product. Complex 1 also reacts with O-2 to yield the corresponding Co-III-eta(1)-ONO2 (2) nitrato analogue. This report is the first to suggest an HNO donor role for {CoNO}(8) with biotargets such as Fe-III-porphyrins.