The complex and harsh tumor microenvironment imped the efficacy of single‐modality tumor therapy. With the advantages of biosafety, organic/inorganic nanohybrids have attracted more and more interest of researchers, and it is critical to investigate the development of highly efficient nanohybrids for multimodality combination therapy of cancers. Herein, a naphthalene diimide‐based polycyclic conjugated molecule (NDI‐S) is designed and synthesized, which has broader light absorption in the near infrared (NIR) region, outstanding photothermal conversion ability, and excellent photostability. Inorganic CoFe2O4 is synthesized via a solvothermal technique, which can produce much more reactive oxygen species (ROS) as a sonosensitizer when activated by ultrasonic (US). NDI‐S and CoFe2O4 are then nanoprecipitated to create the organic/inorganic nanohybrids, NDI‐S@CoFe2O4. According to the results of in vitro and in vivo experiments, NDI‐S@CoFe2O4 can serve as a multifunctional nanoplatform for multimodal treatment of tumors in combination with photothermal/photodynamic/sonodynamic‐ therapy under the guidance of photoacoustic imaging, which provides a new vision of the development of organic/inorganic nanohybrids for cancer theranostics.