Below-mentioned formula (i):(In formula, as for R1 hydrogen atom, showing C1-12 alkyl group, or C1-12 alkoxy group As for R2 showing C1-12 alkyl group or C1-12 alkoxy group R3, R4, R5, R6, as for R7, and R8 showing hydrogen atom or halogen atom R9 shows the monobalent basis which is cut off by the contact with the enzyme or active oxygen kind) with the chemical compound for photosensitization which is displayed. The chemical compound which is displayed with above-mentioned formula (i) receiving the cutting of R9 with the enzyme or active oxygen which is revealed inside the target cell, has had the character which gives the photosensitizer, it is useful with excitation optical lighting the said cell as the medicine for PDT in order to kill and wound selectively.下記の式(I):(式中、R1は水素原子、C1-12アルキル基、又はC1-12アルコキシ基を示し;R2はC1-12アルキル基又はC1-12アルコキシ基を示し;R3、R4、R5、R6、R7、及びR8は水素原子又はハロゲン原子を示し;R9は酵素又は活性酸素種との接触により切断される一価の基を示す)で表される光増感用化合物。上記式(I)で表される化合物は標的細胞内で発現する酵素又は活性酸素によりR9の切断を受けて光増感剤を与える性質を有しており、励起光照射により該細胞を選択的に殺傷するためのPDT用医薬として有用である。
