– Compound 3 (diABZI-V/C-DBCO) functions as an efficient STING agonist. This compound acts by releasing diABZI-amine under the action of cathepsin B to activate STING, thereby inducing the production of interferon and other immune-activating molecules, which enhances the immune system’s response to tumors. In THP1-Dual cells, the EC50 values for STING activation by diABZI-V/C-DBCO and diABZI-amine are 1.47 nM and 0.144 nM, respectively, and in primary mouse splenic cells, the EC50 values are 7.7 µM and 0.17 µM, respectively. diABZI-V/C-DBCO is useful for research in the field of cancer immunotherapy.