Targeted　photodynamic　therapy　is　a　new　promising　therapeutic　strategy　to　overcome　growing　problems　in　contemporary　medicine,　such　as　drug　toxicity　and　drug　resistance.　A　series　of　erlotinib-zinc(II)　phthalocyanine　conjugates　were　designed　and　synthesized.　Compared　with　unsubstituted　zinc(II)　phthalocyanine,　these　conjugates　can　successfully　target　EGFR-overexpressing　cancer　cells　owing　to　the　presence　of　the　small　molecular-　target-based　anticancer　agent　erlotinib.　All　conjugates　were　found　to　be　essentially　non-cytotoxic　in　the　absence　of　light　(up　to　50　mu　m),　but　upon　illumination,　they　show　significantly　high　photo-cytotoxicity　toward　HepG2　cells,　with　IC50　values　as　low　as　9.61-91.77　nm　under　a　rather　low　light　dose　(lambda　=　670　nm,　1.5　J　cm(-2)).　Structure-activity　relationships　for　these　conjugates　were　assessed　by　determining　their　photophysical/photochemical　properties,　cellular　uptake,　and　in　vitro　photodynamic　activities.　The　results　show　that　these　conjugates　are　highly　promising　antitumor　agents　for　molecular-target-based　photodynamic　therapy.