Abstract
Seleno-substituted bis-(boron difluoride)-8-imidazo-dipyrro-methene (BOIMPY) derivatives displayed improved photophysical features over twisted-BOIMPY, such as greater Stokes shifts, while compromising radiative relaxation and intersystem crossing, making them suitable for imaging-guided photodynamic therapy (PDT). One exhibited improved Type I and Type II PDT against cancer cells when activated by near-infrared light. Its potential as a targeted PDT agent for cancer treatment is demonstrated by its remarkable phototoxicity in the nanomolar range and minimal dark toxicity.