The anionic {Fe(NO)(2)}(9) DNIC [(NO)(2)Fe(C3H3N2)(2)](-) (2) (C3H3N2 = deprotonated imidazole) containing the deprotonated imidazole-coordinated ligands and DNICs [(NO)(2)Fe(C3H3N2)(SR)](-) (R = Bu-t (3), Et (4), Ph (5)) containing the mixed deprotonated imidazole-thiolate coordinated ligands, respectively, were synthesized by thiol protonation or thiolate(s) ligand-exchange reaction. The anionic {Fe(NO)(2)}(9) DNICs 2-5 were characterized by IR, UV-vis, EPR, and single-crystal X-ray diffraction. The facile transformation among the anionic {Fe(NO)(2)}(9) DNICs 2-5 and [(NO)(2)Fe((SBu)-Bu-t)(2)](-)/[(NO)(2)Fe(SEt)(2)](-)/[(NO)(2)Fe(SPh)(2)] (-) was demonstrated in this systematic study. Of importance, the distinct electron-donating ability of thiolates serve to regulate the stability of the anionic {Fe(NO)(2)}(9) DNICs and the ligand-substitution reactions of DNICs. At 298 K, DNIC 2 exhibits the nine-line EPR signal with g = 2.027 (a(N(NO)) = 2.20 and a(N(Im-H)) = 3.15 G; Im-H = deprotonated imidazole) and DNIC 3 displays the nine-line signals with g = 2.027 (a(N(NO)) = 2.35 and a(N(Im-H)) = 4.10 G). Interestingly, the EPR spectrum of complex 4 exhibits a well-resolved 11-line pattern with g = 2.027 (a(N(NO)) = 2.50, a(N(Im-H)) = 4.10 G, and a(H) = 1.55 G) at 298 K. The EPR spectra (the pattern of hyperfine splitting) in combination with IR nu(NO) spectra (Delta nu(NO) = the separation of NO stretching frequencies, Delta nu(NO) = similar to 62 cm(-1) for 2 vs similar to 50 cm(-1) for 3-5 vs similar to 43 cm(-1) for [(NO)(2)Fe((SBu)-Bu-t)(2)](-)/ [(NO)(2)Fe(SEt)(2)](-)/[(NO)(2)Fe(SPh)(2)](-)) may serve as an efficient tool for the discrimination of the existence of the anionic {Fe(NO)(2)}(9) DNICs containing the different ligations [N,N]/[N,S]/[S,S].