As　growth　factor　receptor-2　(HER-2),　progesterone　receptor　(PR)　and　estrogen　receptor　(ER)　are　scarce　in　triple-negative　breast　cancer　(TNBC),　it　is　a　great　challenge　to　combat　TNBC　with　high　tumor　specificity　and　therapeutic　efficacy.　Most　traditional　treatments　including　surgical　resection,　chemotherapy,　and　radiotherapy　would　more　or　less　cause　serious　side　effects　and　drug　resistance.　Photodynamic　therapy　(PDT)　has　huge　potential　in　the　treatment　of　TNBC　for　minimal　invasiveness,　low　toxicity,　less　drug　resistance　and　high　spatiotemporal　selectivity.　Inspired　by　the　advantages　of　small-molecule-targeted　PDT　and　the　sensitization　effect　of　myeloid　cell　leukemia-1　(MCL-1)　inhibitor,　a　novel　photosensitizer　BC-Pc　was　designed　by　conjugating　MCL-1　inhibitor　with　zinc　phthalocyanines.　Owning　to　3-chloro-6-methyl-1-benzothiophene-2-carboxylic　acid　(BC)　moiety,　BC-Pc　exhibits　the　high　affinity　towards　MCL-1　and　reduce　its　self-aggregation　in　TNBC　cells.　Therefore,　MCL-1　targeted　BC-Pc　showed　remarkable　intracellular　fluorescence　and　ROS　generation　in　TNBC　cells.　Additionally,　BC-Pc　can　selectively　sensitize　TNBC　cells　to　ROS-induced　damage,　resulting　in　improved　therapeutic　effect　to　TNBC　cells　and　negligible　toxicity　to　normal　cells.　More　importantly,　BC-Pc　can　effectively　inhibit　the　migration　and　invasion　of　TNBC　cells,　and　enhance　immune　response,　all　of　which　will　be　beneficial　to　eradicate　TNBC.　To　the　best　of　our　knowledge,　BC-Pc　is　the　novel　MCL-targeted　photosensitizer,　which　owns　the　amplified　ROS-induced　lethality　and　anticancer　immune　response　for　TNBC.　Overall,　our　study　provides　a　promising　strategy　to　achieve　targeting　and　highly　efficient　therapy　of　TNBC.　©　2022　Elsevier　Inc.