Herein, we report a rare example of cationic three‐dimensional (3D) metal‐organic framework (MOF) of [Cu5Cl3(TMPP)]Cl5 ⋅ xSol (denoted as Cu−TMPP; H2TMPP=meso‐tetrakis (6‐methylpyridin‐3‐yl) porphyrin; xSol=encapsulated solvates) supported by [Cu8Cl6]10+ cluster secondary building units (SBUs) wherein the eight faces of the Cl−‐based octahedron are capped by eight Cu2+. Surface‐area analysis indicated that Cu−TMPP features a mesoporous structure and its solvate‐like Cl− counterions can be exchanged by BF4−, PF6−, and NO3−. The polyvinylpyrrolidone (PVP) coated Cu−TMPP (denoted as Cu−TMPP−PVP) demonstrated good ROS generating ability, producing ⋅OH in the absence of light (peroxidase‐like activity) and 1O2 on light irradiation (650 nm; 25 mW cm−2). This work highlights the potential of Cu−TMPP as a functional carrier of anionic guests such as drugs, for the combination therapy of cancer and other diseases. [ABSTRACT FROM AUTHOR]