The recent realization that nitric oxide is a biological messenger in many physiological processes has brought about a renewed interest in its chemistry,particularly its iron complexes that are central to the role of nitric oxide in the body.Spectroscopic evidence would appear to implicate species of “Fe(NO)2+” type are responsible for a variety of processes ranging from polymerization,carcinogenesis,to nitric oxide stores.This work describes two types of self assembled clusters of non-heme iron nitrosyl complexes.One type is a tetrameric cluster of [Fe(NO)2(L)]4(L = Imidazoles),resulted from the interactions of Fe(NO)2 with a series of substituted imidazoles,and the other is the dimeric Roussins red salt esters [Fe(μ-RS)(NO)2]2 synthesized by the reaction of Fe(NO)2(CO)2 with thiols or thiolates.A combination of different techniques,such as NMR,IR,EPR,electrochemistry,and X-ray crystallography,in studying the nanostructures and dynamics of these systems are discussed.