Herein, an small-molecule organic nanoparticles, BNTP NPs, has been synthesized. Due to its strong and broad absorption spectra and tumor targeting, BNTP NPs is used as a photothermal agent with photothermal conversion efficiency of 23.2%. BNTP NPs can target tumors, realize tumor diagnosis and suppress the growth of tumor effectively both in vitro and in vivo. Xenon lamp instead of laser is used as light source of BNTP NPs to make PTT safer. No obvious toxicity reaction is observed from histologic analysis and body weight of mice. The results confirm that BNTP NPs have potential for clinical application of PTT.