Two　novel　luminescent　hetero-trinuclear　complexes　[Pt2Ag(mu-dpppy)　2(C=CC6H4R-4)(4)](ClO4)　(R　=　H,　1;　R　=　CH3,　2;　dpppy　=　2,6-bis(diphenylphosphino)　pyridine)　were　synthesized　by　the　self-assembly　reaction　between　[Pt(C=CC6H4R-4)(4)](2-)　and　[Ag-2(mu-dpppy)　3](2+)　and　characterized　by　elemental　analyses,　electrospray　ionization　mass　spectrometry,　and　H-1　NMR　and　P-31{1H}　NMR　spectroscopy　and　by　X-ray　crystallography　for　complex　2.　Two　Pt2Ag　complexes　show　strong　luminescence　in　the　solid　state,　but　exhibit　weak　emission　in　CH2Cl2　solution　and　in　acetonitrile-water　(1　:　1,　v　:　v)　solution　at　room　temperature.　To　overcome　the　limitations　of　low　water　solubility　and　weak　emission　in　solutions,　a　new　kind　of　luminescent　Pt2Ag@　SiO2　nanoparticles　was　prepared　by　incorporating　the　new　Pt2Ag　acetylides　into　monodisperse　silica　nanoparticles.　It　is　noted　that　Pt2Ag@　SiO2　nanoparticles　exhibit　strong　luminescence　in　aqueous　solution,　and　cyanide　anions　tend　to　decrease　their　luminescence　intensity　in　NaHCO3-NaOH　buffer　solution.　Based　on　this,　a　novel　nanosensor　for　highly　sensitive　detection　of　cyanide　anions　was　developed　in　the　range　of　0.1-10.0　mu　M.