Transformation of dinitrosyl iron complexes (DNICs) [(NO)(2)Fe(SR)(2)](-) (R = Et, Ph) into [4Fe-4S] clusters (Fe4S4(SPh)(4)](2-) in the presence of [Fe(SPh)(4)](2-/1-) and S-donor species S-8 via the reassembling process ([(NO)(2)Fe(SR)(2)](-) -> [Fe4S3(NO)(7)](-) (1)/[Fe4S3(NO)(7)](2-) (2) -> [Fe4S4(NO)(4)](2-) (3) -> [Fe4S4(SPh)(4)](2-) (5)) was demonstrated. Reaction of [(NO)(2)Fe(SR)(2)](-) (R = Et, Ph) with S-8 in THF, followed by the addition of HBF4 into the mixture solution, yielded complex [Fe4S3(NO)(7)](-) (1). Complex [Fe4S3(NO)(7)](2-) (2), obtained from reduction of complex 1 by [Na][biphenyl], was converted into complex [Fe4S4(NO)(4)](2-) (3) along with byproduct [(NO)(2)Fe(SR)(2)](-) via the proposed [Fe4S3(SPh)(NO)(4)](2-) intermediate upon treating complex 2 with 1.5 equiv of [Fe(SPh)(4)](2-) and the subsequent addition of 1/8 equiv of S-8 in CH3CN at ambient temperature. Complex 3 was characterized by IR, UV-vis, and single-crystal X-ray diffraction. Upon addition of complex 3 to the CH3CN solution of [Fe(SPh)(4)](-) in a 1:2 molar ratio at ambient temperature, the rapid NO radical-thiyl radical exchange reaction between complex 3 and the biomimetic oxidized form of rubredoxin [Fe(SPh)(4)](-) occurred, leading to the simultaneous formation of [4Fe-4S] cluster [Fe4S4(SPh)(4)](2-) (5) and DNIC [(NO)(2)Fe(SPh)(2)](-). This result demonstrates a successful biomimetic reassembly of [4Fe-4S] cluster [Fe4S4(SPh)4]2- from NO-modified [Fe-S] clusters, relevant to the repair of DNICs derived from nitrosylation of [4Fe-4S] clusters of endonuclease III back to [4Fe-4S] clusters upon addition of ferrous ion, cysteine, and IscS.