The biological interplay between Fe and NyOx is significant to both human physiology and the remediation of global pollution. The interconversion of NyOx species is primarily mediated by metalloenzymes, in which Fe plays a critical role. Due to their critical role in biology and the environment, the study of Fe-NyOx interactions is of fundamental interest in coordination chemistry. Additionally, thiol-containing biomolecules have direct interaction with Fe-NyOx. For example, Fe(III)-NO2 complexes react with thiols to NO or HNO and the corresponding sulfenic acids. Given the complex interplay between NyOx, Fe, and thiols, there is a need to rationalize this intricate chemistry through model complexes. Our approach involves the design and synthesis of modular non-heme complexes in which donor strength, flexibility, and secondary-sphere interactions are readily tuned. This methodology has facilitated the isolation and characterization of the first non-heme {FeNO}8 and Fe(II)(NO2)2 complexes, and allowed for the first study of their reactivity with Fe(III)-porphyrins, Fe(III)-myoglobin, thiols, and protons. From these reactivity studies we have demonstrated nitroxyl-transfer to metMb to give MbNO, thus outlining the proof-of-principle for the rational design of metal-based HNO donors. Moreover, we have demonstrated that reactions of non-heme {FeNO}7/8 complexes with thiols ultimately leads to various dinitrosyl iron complexes (DNICs) in an oxidation state dependent manner. These results suggest a possible route to DNIC formation from non-heme {FeNO}7/8 complexes in biology. Lastly, the development of non-heme NO2- reduction catalysts is discussed. In the presence of H+/thiols the selective and catalytic conversion of NO2- to NO(g) is observed. However, in the presence of only thiols, a net three-electron reduction of Fe(II)(NO2)2 to the Fe(I)(NO)2 DNIC is observed, and suggests a possible role for Fe-NO2 and thiols in the formation of biological DNICs. Described in this dissertation is the synthesis, characterization, and reactivity of a series of non-heme Fe-NOx complexes, which provides the basis for the development of non-heme NO2 reduction catalysts and Fe-based HNO donor molecules for the purpose of cardiovascular therapies and environmental remediation.