Facile preparation of highly thermosensitive N-doped carbon dots and their detection of temperature and 6-mercaotopurine

•The highly thermosensitive N-doped carbon dots (N-CDs) were prepared by NH4Cl as an inorganic dopant.•The N-CDs display marvelous thermosensitive fluorescence response with good linear relationship, reversibility, and restorability.•The mechanism of the thermosensitive fluorescence response of N-CDs was the activation of nonradiative channels.•The N-CDs can be applied to selective detection of 6-mercaptopurine based on inner filter effect and no additional complex nanomaterials are required.