Structural, electronic and magnetic properties of 3d transition metal tetraoxide TMO4 superhalogen clusters doped single vacancy (SV) and divacancy (DV) monolayer graphene have been studied using first-principles calculations. We found that in both cases of TMO4 cluster substitution, all the impurity atoms are tightly bonded with graphene, having significant formation energy and large charge transfer occurs from graphene to TMO4 clusters. CrO4 and MnO4 substituted SV graphene structures exhibit dilute magnetic semiconductor behavior in their spin down channel with 2.15 mu(B) and 3.51 mu(B) magnetic moment, respectively. However, CoO4, FeO4, TiO4 and NiO4 substitution into SV graphene, leads to Fermi level shifting to conduction band, thereby causing the Dirac cone to move into valence band and a band gap appears at high symmetric K-point. Interestingly, CoO4, CrO4, FeO4 and MnO4 substituted DV graphene structures exhibit dilute magnetic semiconductor behavior in their spin up channel with 1.74 mu(B), 3.27 mu(B), 3.09 mu(B) and 1.99 mu(B) magnetic moment, respectively. Detailed analysis of density of states (DOS) plots show that d orbitals of 3d TM atoms should be responsible for inducing magnetic moments in graphene. We believe that our results are appropriate for experimental exploration and graphene-based spintronic and magnetic storage devices. (C) 2017 Elsevier B.V. All rights reserved.