A　relay　strategy　has　been　proposed　to　design　a　new　Hg2+　chemodosimeter　(TPE-S),　by　coupling　Hg2+-promoted　deprotection　reaction　with　ketone-enol　isomerization,　realizing　the　multistage　amplifying　effect.　Changes　in　both　of　color　and　fluorescence　could　occur　immediately,　and　TPE-S　displayed　high　selectivity　for　Hg2+,　other　metal　ions　(Ag+,　Fe3+,　Cu2+,　Pb2+,　Co2+,　Cr3+,　Al3+,　Cd2+,　Mg2+,　Mn2+,　Ba2+,　Fe2+,　Ca2+,　Ni2+,　Zn2+,　Li+,　K+　and　Na+)　gave　nearly　no　disturbance　to　the　sensing　process.　When　fabricated　as　test　strips　similar　to　pH-indicator　papers,　immediate　color　change　from　colorless　to　purple　could　be　visually　observed　by　naked-eyes　without　the　aid　of　any　additional　equipment,　with　the　detection　limit　as　low　as　1　x　10(-7)　M　(Hg2+　in　aqueous　solution).　Due　to　its　easy　synthesis,　high　selectivity　and　sensitivity,　combined　with　the　portable　test　strips,　TPE-S　could　be　developed　as　a　convenient　and　cost-effective　tool　for　the　detection　of　Hg2+　in　on-site　inspections.