Metal　organic　frameworks　(MOFs)　contain　ordered　pores　capable　of　encapsulating　varied　types　of　guests　and　provide　a　platform　to　expand　the　flexibility　and　versatility　of　the　host-guest　composites.　Herein,　by　encapsulating　CH3NH3PbBr3　NPS　into　Ln-MOFs　(Ln　=　La,　Nd,　Pr,　Sm),　four　CH3NH3PbBr3@Ln-MOFs　host-guest　composites　were　fabricated　and　served　as　a　bifunctional　platform.　The　temperature-dependent　luminescence　properties　of　the　CH3NH3PbBr3@Ln-MOFs　were　explored　and　the　results　revealed　their　tuneable　green　luminescence　perfor-mance.　In　particular,　the　CH3NH3PbBr3@Sm-MOF　exhibits　a　variety　of　colours　from　green　to　blue　to　purple　and　an　excellent　quantum　yield　of　0.98.　The　photocurrent　responses　and　theoretical　calculations　reveal　the　enhancement　mechanism　of　CH3NH3PbBr3　on　charge-hole　separation　owing　to　its　unique　host-guest　synergy.　Moreover,　the　CH3NH3PbBr3@Sm-MOF　exhibits　the　excellent　electrical　bi-stability　with　a　high　ON/OFF　ratio　of　104.　Hence,　the　CH3NH3PbBr3@Ln-MOFs　host-guest　composites　are　promising　candidates　for　a　new　generation　of　photovoltaic,　light-emitting,　and　switching　memories　devices.