In　this　work,　one　mononuclear　complex　CH3CNFeII(eq-Py(4)PzMe(2))　(1)　and　two　binuclear　complexes　Cp(dppe)(MCNFeII)-C-II(eq-Py(4)PzMe(2))　(M　&　nbsp;=&　nbsp;Ru　&　nbsp;2,　Fe　&　nbsp;3;　Cp　&　nbsp;=&　nbsp;cyclopentadiene,　dppe　&　nbsp;=&　nbsp;1,2-bis(diphenylphosphino)ethane,　eq-Py(4)PzMe(2)&　nbsp;=&　nbsp;2-(1-(6-(1,1-di(pyridin-2-yl)ethyl)pyridin-2-yl)-1-(pyridin-2-yl)ethyl)pyrazine)　were　synthesized.　Combined　with　the　TDDFT　calculations,　the　metal-to-ligand　charge　transfer　(MLCT)　properties　of　all　the　compounds　were　investigated.　The　results　show　that　for　the　mononuclear　complex,　the　MLCT　originates　from　Fe-II　&　nbsp;to　the　pyrazine　(Pz)　component　of　the　eq-Py(4)PzMe(2)&　nbsp;ligand.　After　the　substitution　of　CH3CN　in　complex　&　nbsp;1　&　nbsp;by　the　half-sandwich　fragment　Cp(dppe)(MCN)-C-II,　the　binuclear　complexes　&　nbsp;2　&　nbsp;and　&　nbsp;3　&　nbsp;exhibit　the　MLCT　transition　from　the　neighboring　Fe-II　&　nbsp;atom　to　the　Pz　component　of　the　eq-Py(4)PzMe(2)&　nbsp;together　with　some　contributions　from　the　remote　M-II.　With　the　increase　of　the　electron-donating　ability　from　CH3CN,　Cp(dppe)(RuCN)-C-II　to　Cp(dppe)(FeCN)-C-II,　the　MLCT　transition　energy　decreases.　Furthermore,　with　the　decrease　of　pH　value,　all　the　MLCT　absorption　bands　are　significantly　redshifted　by　160　&　nbsp;nm　or　more,　and　the　extent　of　these　red　shifts　increases　from　complex　&　nbsp;1　&　nbsp;to　&　nbsp;2,　to　&　nbsp;3.