Rational Improvement of Molar Absorptivity Guided by Oscillator Strength: A Case Study with Furoindolizine‐Based Core Skeleton

The rational improvement of photophysical properties can be highly valuable for the discovery of novel organic fluorophores. Using our new design strategy guided by the oscillator strength, we developed a series of full‐color‐tunable furoindolizine analogs with improved molar absorptivity through the fusion of a furan ring into the indolizine‐based Seoul fluorophore. The excellent correlation between the computable values (oscillator strength and theoretical S(0)–S(1) energy gap) and photophysical properties (molar absorptivity and emission wavelength) confirmed the effectualness of our design strategy.