Unsymmetric thieno-phospha-rhodamines: A new class of near-infrared fluorescent probes for stimuli-responsive organelle imaging

We report thieno-phospha-rhodamine (TPR) dyes as a novel class of near-infrared (NIR)-emissive fluorophores featuring an unsymmetric π-skeleton. TPR dyes exhibit emission maxima near 800 nm, large Stokes shifts, and excellent photostability. Notably, TPR-Et displays dual organelle localization that dynamically responds to changes in mitochondrial membrane potential and lysosomal pH.