Fluorescent merocyanines: from fundamental properties to applications as molecular probes, in bioimaging and as emissive dye aggregates

. reduced radiative rates due to co-facial stacking, leading to (undesired) H-type coupling with the concomitant decrease of oscillator strength for the lowest excitonic state. Here, we will highlight examples where the first process prevails, leading to emission enhancement, as demonstrated for solid state materials as well as self-assembled aggregates and foldamers in solution.