Vol. 10, Issue 1, Part C (2024)

Abstract
Hemicyanine dyes are widely used in various fields, including fluorescence imaging, optical data storage, and photodynamic therapy. The activatable fluorescent probes for diverse biological analytes presents a challenge due to chemical instability and photoinstability. This is exemplified by naphthalene-based hemicyanines incorporating the common hemicyanine moiety, 2-indolium. However, these challenges can be effectively addressed by employing a 4-pyridinium derivative, which also exhibits excellent two-photon imaging capabilities.