ABSTRACT Objective This study aimed to prepare a porphyrin hybrid hollow mesoporous organosilica molecular probe (TCPP@HMON, referred to as THMON), and explore its in vitro ultrasound imaging capability and therapeutic effects on glioma through sonodynamic therapy (SDT). Methods THMON was synthesized via an in situ growth method. Its morphology was characterized by transmission electron microscopy (TEM), while its particle size and zeta potential were measured by a Malvern particle size and zeta potential analyzer. The absorbance was detected by a UV-Vis spectrophotometer, and the encapsulation efficiency and loading capacity of TCPP were calculated. Silicon (Si) content was quantified by inductively coupled plasma mass spectrometry (ICP-MS). In vitro ultrasound images of the THMON at varying concentrations were acquired, and the contrast enhancement was quantitatively analyzed. The singlet oxygen sensor green (SOSG) fluorescence probe was employed to evaluate the reactive oxygen species generation capability of THMON. The SDT efficacy of THMON was verified by the CCK-8 assay. The in vivo biosafety of THMON was further evaluated through Balb/c mice. Results THMON exhibited a uniform hollow mesoporous spherical structure, with an average particle size of (121.5 ± 24.3) nm and an average surface potential of (-78.5 ± 1.1) mV. The encapsulation efficiency and loading capacity of TCPP were 35.9% and 3.0wt%, respectively. THMON significantly enhanced the B-mode ultrasound imaging, with echo intensity positively correlated to its concentration. THMON could significantly kill tumor cells through SDT effect under ultrasound irradiation. Blood assay verified that THMON has good biosafety. Conclusion THMON was successfully synthesized in this study. It not only improved in vitro ultrasound imaging performance but also effectively inhibited glioma proliferation via the sonodynamic effect. KEY WORDS Organosilica molecular probe; Ultrasound imaging; Sonodynamic therapy