In this study, we reported the design and synthesis of a conceptually novel ligand architecture -exhibiting a rigid pentacoordinate metal-binding cage integrated within a cavitand scaffold. The corresponding Mn(II) metallocavitand reacted with oxo-transfer reagents, generating a highly reactive terminal Mn(IV)-oxo species deeply buried within its molecular cavity. The steric protection provided by the cavitand enabled a full characterization of this elusive species not only through various spectroscopic techniques (UV-vis, EPR, HRMS), but also -for the first time for such a pseudooctahedral Mn(IV)-oxo complex -by means of X-ray crystallography.