Novel aza-BODIPY derivatives substituted with heavy atoms such as bromine and iodine were synthesized, and their triplet and singlet oxygen generation efficiencies have been investigated. These derivatives showed absorption in the NIR region with high molar extinction coefficients. The dye substituted with four iodine atoms showed yields of Phi(T) = 0.78 and Phi(O-1(2)) = 0.70, which are the highest values so far obtained for the aza-BODIPY derivatives.
