Abstract Using first principles method we elaborately discuss the magnetic, elastic and optical properties of pure, Zn and O vacant ZnO2. It is found that the electronic structure and band gap of ZnO2 is not sensitive to the active on-site Coulomb interaction term Ud, but found to be depending on the term Up. The role of orbitals subject to the correlation is thus completely opposite for the case of ZnO2 in respect of ZnO. Interestingly, the Zn vacancy converts ZnO2 as “d0 magnet”. Indeed, our analysis show that, Zn vacancy transmuted O22− state into O2δ+2− state, indicating the partially filled π∗ states are the governing reason for the d0 magnetism. Both HSE06 and PBE0 functional confirm the same. The similar phenomena has been observed for other peroxide materials XO2 (X=Mg, Ca, Sr, Ba) studied here. Our results suggest that this class of materials can be studied further to exploit its potential in spintronic devices. Further the elastic properties have been estimated for pure ZnO2 at different pressures and for Zn and O vacant ZnO2 to know the stability of the system. Zn vacancy in ZnO2 also tunes optical properties, indicating its potential application in other areas.