Synthesis, characterization, electronic structure, and redox reactions of a mononuclear {FeNO}7 complex with a very high N-O stretching frequency in solution are presented. Nitrosylation of [(LKP)Fe(DMF)]2+ (1) (LKP = tris((1-methyl-4,5-diphenyl-1H-imidazol-2-yl)methyl)amine) produced a five-coordinate {FeNO}7 complex, [(LKP)Fe(NO)]2+ (2). While complex 2 could accommodate an additional water molecule to generate a six-coordinate {FeNO}7 complex, [(LKP)Fe(NO)(H2O)]2+ (3), the coordinated H2O in 3 dissociates to generate 2 in solution. The molecular structure of 2 features a nearly linear Fe-N-O unit with an Fe-N distance of 1.744(4) Å, N-O distance of 1.162(5) Å, and <Fe-N-O angle of 178.3°, while that of 3 features a slightly bent Fe-N-O unit with an Fe-N distance of 1.750(5) Å, N-O distance of 1.157(6) Å, and <Fe-N-O angle of 173.3°. Complex 2 displays a very high N-O stretching frequency of 1844 cm-1 in dichloromethane and readily dissociates NO when dissolved in coordinating solvents such as acetonitrile or N,N-dimethylformamide. Investigation of the reduction of 2 by FTIR-SEC and EPR spectroscopy shows the generation of a {Fe(NO)2}9 species, and the results have been corroborated by electronic structure calculations. Furthermore, the reaction of 2 with bezenethiolate (PhS-) and hydrosulfide (HS-) allowed the unambiguous characterization of a dinitrosyl iron complex (DNIC), [Fe(SPh)2(NO)2]1-, and an unprecedented complex, [{(LKP)Fe(DMF)}2{Fe6S6(NO)6}]2+, featuring an iron-sulfur prismane dianion.