The Orthogonal α‐meso‐Linked bisBODIPY Photosensitizers Demonstrate Effective Two‐Photon Fluorescence Imaging and Photodynamic Therapy

Abstract Hypoxic tumor microenvironments pose significant challenges to the clinical translation of cancer photodynamic therapy (PDT). While heavy atom‐free Type‐I boron dipyrromethenes (BODIPYs) photosensitizers can alleviate this challenge by reducing oxygen dependency, but they remain scarce. Herein, heavy‐atom‐free α,meso ‐linked bisBODIPYs were designed and synthesized. These bisBODIPYs exhibit remarkable red‐shifted emission (λemmax ~670 nm), large Stokes shifts (~4480 cm −1 ) and they are capable of producing both superoxide anion (O 2 ⋅ − ) and singlet oxygen ( 1 O 2 ) in solution and cells. Additionally, they offer a wide PDT treatment window, ranging from 0.26 to 83.5 μM. Furthermore, these bisBODIPYs also demonstrate superior two‐photon fluorescence, promising for surgical navigation and integrating diagnosis with treatment.