A　series　of　the　luminescent　Re(I)　complexes,　[Re(bpy-(CH　2OH)2)(CO)3(L1)],　[Re(bpy-(CH　2OH)2)(CO)3(L2)]+,　[Re(bpy-(CH　2OH)2)(CO)3(L3)]+,　and　[Re(bpy-(CH2OH)2)(CO)3(L4)]　((bpy-(CH　2OH)2　=　4,4′-bis(hydroxymethyl)-2,2′-　bipyridine;　L1　=　4-pyridylmethyl　lipoate;　L2　=　[1,2]dithiolane-3-pentyl　4-pyrindylacetate;　L3　=　4-pyridinyl-methanol;　L4　=　4-pyridinylmethyl　pentanoate),　were　synthesized　and　characterized.　The　photophysical　properties　and　cytotoxicity　of　the　complexes　and　the　sensing　of　esterase　based　on　the　gold　nanoparticles　(Au-NPs)　modified　with　the　complexes　were　also　studied.　The　intense　luminescence　of　the　Re(I)　complexes　was　quenched　efficiently　by　Au-NPs　due　to　the　energy　and　electron　transfer　between　the　Re(I)　fluorophores　and　Au-NPs.　Upon　addition　of　esterase　to　the　mixture,　the　emission　of　the　Re(I)　complexes　1　and　2　system　was　enhanced　significantly　by　the　release　of　the　Re(I)　complexes　from　the　surface　of　the　Au-NPs.　©　2012　American　Chemical　Society.