Small-molecular-target-based　photodynamic　therapy-a　promising　targeted　anticancer　strategy-was　developed　by　conjugating　zinc(II)　phthalocyanine　with　a　small-molecular-target-based　anticancer　drug.　To　prevent　self-aggregation　and　avoid　problems　of　phthalocyanine　isomerization,　two　silicon　phthalocyanines　di-substituted　axially　with　erlotinib　have　been　synthesized　and　fully　characterized.　These　conjugates　are　present　in　monomeric　form　in　various　solvents　as　well　as　culture　media.　Cell-based　experiments　showed　that　these　conjugates　localize　in　lysosomes　and　mitochondria,　while　maintaining　high　photodynamic　activities　(IC50　values　as　low　as　8　nm　under　a　light　dose　of　1.5　Jcm(-2)).　With　erlotinib　as　the　targeting　moiety,　two　conjugates　were　found　to　exhibit　high　specificity　for　EGFR-overexpressing　cancer　cells.　Various　poly(ethylene　glycol)　(PEG)　linker　lengths　were　shown　to　have　an　effect　on　the　photophysical/photochemical　properties　and　on　in　vitro　phototoxicity.