Heteroatom substitution controlled luminescent property and excited state intramolecular proton transfer (ESIPT) process of novel benzothiazole-based fluorophore: A TD-DFT investigation

•The experimental absorption and fluorescence peaks of BTFM-OH were reproduced.•As the atomic electron-withdrawing ability of heteroatom reduces from O to S and Se, the absorption and fluorescence peaks red-shifted from BOFM-OH to BTFM-OH and BSeFM-OH.•The ground state and excited state HOMO-LUMO gaps decreased in the order of BOFM-OH > BTFM-OH > BSeFM-OH.•With the weakened electron-withdrawing ability of heteroatom (from O to S and Se), the ESIPT process occur much easier from BOFM-OH to BTFM-OH and BSeFM-OH.