In　previous　works,　we　have　proposed　the　thermodynamic　performance　limit　analysis　methodology　for　the　organic　Rankine　cycle　for　analyzing　the　impact　of　working　fluid　properties　on　system　performance.　Here　the　concept　is　extended　to　the　thermo-economic　performance　limits,　and　is　applied　to　a　combined　heat　and　power　system　based　on　an　organic　Rankine　cycle.　Working　fluids　are　characterized　with　8　characteristic　thermodynamic　and　transport　properties　based　on　a　corresponding　state　model　and　a　residual　entropy　scaling　approach.　The　8　fluid　characteristic　properties　along　with　3　system　operational　parameters　are　optimized　using　a　multi-objective　genetic　algorithm;　a　Monte　Carlo　algorithm　is　further　adopted　to　avoid　sub-optimal　convergences.　As　the　result,　the　performance　limits　could　be　well　represented　by　the　trade-off　(Pareto　front)　between　the　maximized　thermal　efficiency　and　minimized　payback　period.　The　impact　of　the　fluid　characteristic　properties　on　both　thermodynamic　and　economic　targets　is　investigated　and　ultimately　guided　the　choice　of　working　fluids:　low　molar　mass,　low　thermal　conductivity　scaling　factor,　high　viscosity　scaling　factor　and　high　critical　pressure　are　always　preferred.　“Wet”　working　fluid　is　preferred　for　a　high　thermal　efficiency　while　“dry”　working　fluid　is　favored　for　a　short　payback　period.　Critical　temperature　has　the　most　profound　impact,　while　ideal　gas　isobaric　heat　capacity　and　acentric　factor　have　negligible　impacts.　The　choice　of　working　fluid,　system　design　(e.g.,　recuperative　effectiveness)　and　system　operational　parameters　(e.g.,　evaporation　temperature)　highly　depends　on　the　given　hot　sources　and　the　preferences　to　the　thermodynamic　and　economic　targets.　©　2023　The　Authors