The magnetic properties and Mott transition of the half-filled Hubbard model on the 1/5 depleted square lattice with frustration is studied at zero temperature by the variational cluster approximation. The (π, π) Néel ordering (AF) is stable in a wide region of the phase diagram and almost completely veils the non-magnetic Mott transition for the unfrustrated case. However, AF is severely suppressed by the frustration and even with moderate frustrations the non-magnetic Mott transition takes place in the range where the intra-dimer hoppings are larger than the intra-plaquette hoppings.PACS numbers: 71.30.+h, 71.10.Fd, 71.27.+a, Introduction.-When the kinetic and Coulomb repulsion energies are competing, low-dimensional materials exhibit a variety of phenomena like superconductivity, Mott transition, and spin liquid, depending on their lattice structures and degrees of the geometric frustrations. One of the interesting lattice structures is the 1/5-depleted square lattice (See Fig. 1 (a)) realized e.g. by CaV 4 O 9 [1] and iron selenide families [2]. This is a nonBrave lattice and its multi-band structure will provide greater flexibility in controlling the electronic properties of materials of this lattice structure. In the limit of the infinite Coulomb repulsion, the (π, π) Néel ordering (See Fig. 1 (b) and (c)) separates two spin gapped states, one adiabatically connected to decoupled dimers, the other connected to decoupled plaquettes, by the second order quantum transition [3][4][5][6][7][8][9]. As for the effect of the electron correlations, the Mott transition was recently studied using the Hubbard model by cluster dynamical meanfield theory(CDMF) [10], but this analysis assumed the non-magnetic ground state and if the Mott transition is veiled or not by the (π, π) Néel ordering is not clear. The magnetic properties are investigated by the determinant quantum Monte Carlo(DQCM) [11], which reports that the dominant magnetism is the (π, π) Néel ordering, but the Mott transition was not analyzed. Moreover, the effect of the next nearest hoppings, which is in general not negligible [7,8] and expected to largely affect the magnetic properties, was not considered in these analyses [10,11]. In this paper we investigate the magnetic phase diagram and Mott transition in the half-filled Hubbard model on the 1/5-depleted square lattice taking into account the effect of the frustration at zero temperature by the variational cluster approximation (VCA).