Discovery of a Full‐Color‐Tunable Fluorescent Core Framework through Direct CH (Hetero)arylation of N‐Heterocycles

All the colors of the rainbow! A full coverage of emission wavelengths in the visible region (405–616 nm) with large Stokes shifts in C3-Indo-Fluor may be straightforwardly and succinctly achieved by the palladium-catalyzed direct CH arylation of indolizines at the C3 position of the pyrrole ring (see figure). The fluorophores have successfully marked A375 cells.