A　series　of　novel　silicon(IV)　phthalocyanines　conjugated　axially　with　different　nucleoside　moieties　(uridine,　5-methyluridine,　cytidine,　and　5-N-cytidine　derivatives)　have　been　synthesized　and　evaluated　for　their　photodynamic　activities.　The　uridine-containing　compound　1　exhibits　the　highest　photocytotoxicity　against　HepG2　human　hepatocarcinoma　cells　with　an　IC50　value　as　low　as　6　nM,　which　can　be　attributed　to　its　high　cellular　uptake　and　non-aggregated　nature　in　the　biological　media.　This　compound　shows　high　affinity　toward　the　mitochondria　of　HepG2　cells　and　causes　cell　death　mainly　through　apoptosis　upon　illumination.　The　result　indicates　that　1　is　a　highly　promising　photosensitizer　for　photodynamic　therapy.