S:　Mercury　ions　(Hg2+)　are　highly　toxic　and　prone　to　bioaccumulation,　showing　a　strong　attraction　to　proteins　and　enzymes　that　contain　sulfur.　Even　minute　quantities　of　Hg2+　can　lead　to　severe　health　issues.　Given　that　mitochondria　are　a　primary　target　organelle　of　Hg2+,　it　is　essential　to　create　a　probe　that　can　accurately　detect　Hg2+　within　intracellular　mitochondria.　In　this　study,　we　developed　two　innovative　Ir(III)　complex　probes　that　emit　near-infrared　light.　The　crystal　structure　of　Ir2　was　determined　using　X-ray　techniques,　which　reveals　that　Ir2　contains　a　pyridine　group　capable　of　recognizing　Hg2+　and　targeting　mitochondria,　allowing　for　the　precise　identification　of　Hg2+　both　in　vitro　and　within　the　mitochondria　of　living　cells.　Additionally,　these　two　novel　near-infrared　phosphorescent　Ir(III)　complexes　demonstrate　significant　capabilities　in　producing　ROS　including　singlet　oxygen,　·O2−　and　·OH,　which　renders　them　effective　photosensitizers　under　visible　light　exposure　for　photodynamic　therapy　(PDT).　This　research　offers　a　promising　approach　for　detecting　Hg2+　in　vitro　and　in　the　mitochondrial　microenvironment　of　living　cells,　which　have　some　implications　for　the　future　development　of　pertinent　transition　metal　complexes　for　mitochondria-targeted　photodynamic　therapy　in　cancer　cells.　©　2025