Extensive spectral tuning of the proton transfer emission from 550 to 675 nm via a rational derivatization of 10-hydroxybenzo[h]quinoline

Via a systematic derivatization of the excited-state intramolecular proton-transfer system, 10-hydroxybenzo[h] quinoline, the proton-transfer emission can be extensively tuned from 550 nm (1) to 675 nm (6), in which amplified spontaneous emission was readily observed for 1-3, generating a new family of proton transfer laser dyes.