Modeling optical signatures and excited-state reactivities of substituted hydroxyphenylbenzoxazole (HBO) ESIPT dyesElectronic supplementary information (ESI) available: (i) Computational details; (ii) delta ρ plots; (iii) relaxed O-H PES scans; (iv) data for the protonated isomer of 2; (v) additional computed UV/vis spectra. See DOI: 10.1039/c3cp54703e

The potential energy surfaces of dyes displaying strong excited-state intramolecular proton transfer (ESIPT) are investigated with the help of ab initio tools. It allows us to rationalize the interplay between the excited-state transition free energies and the observed optical signatures. The potential energy surfaces of dyes displaying strong excited-state intramolecular proton transfer (ESIPT) are investigated with the help of ab initio tools and compared to experimental results.