A　series　of　the　new　ruthenium(II)　complexes　with　different　number　of　aldehyde　groups　have　been　synthesized　and　characterized　for　the　simple　and　selective　sensing　of　homocysteine　(Hcy)　and　cysteine　(Cys).　The　reaction　of　these　ruthenium(II)　complexes　with　Hcy　and　Cys　afforded　thiazinane　or　thiazolidine　derivatives　which　resulted　in　the　obvious　changes　in　the　UV-visible　spectra　and　strong　enhancement　of　the　luminescence　intensity　of　the　system.　The　luminescence　enhancement　of　[Ru(dmb)(2)(L2)](2+)　(dmb:　4,4＇-dimethyl-2,2＇-bipyridine)　showed　a　good　linearity　in　the　concentration　of　4.2-350　mu　M　and　6-385　mu　M　with　the　detection　limits　of　0.3　mu　M　and　1　mu　M　for　Hcy　and　Cys,　respectively.　The　absorption　and　emission　bands　from　metal-to-ligand　charge　transfer　transition　in　the　visible　region　and　the　large　Stokes　shift　of　the　ruthenium(II)　complex　chromophore　made　it　suitable　for　biological　applications.　(C)　2010　Elsevier　Inc.　All　rights　reserved.