Investigation　of　the　Pt-B-O　system　reveals　the　first　magnesium　platinum　borate　Mg3Pt(BO3)(2)O-2　obtained　from　the　high　temperature　flux　method.　The　compound　crystallizes　in　the　centrosymmetric　monoclinic　space　group　C2/m　(no.　12)　with　the　lattice　parameters　of　a　=　16.8073(8)　angstrom,　b　=　3.10610(1)　angstrom,　c　=　5.2107(2)　angstrom,　and　beta　=　90.546(4)degrees　(Z　=　2).　The　crystal　structure　of　Mg3Pt(BO3)(2)O-2　is　based　upon　isolated　BO3　triangles　and　PtO6　and　MgO6　octahedra.　The　PtO6　octahedra　are　connected　with　each　other　in　an　edge-sharing　manner　forming　one　dimensional　(1D)　chains.　Each　of　the　PtO6　octahedra　links　with　two　BO3　units　to　form　anionic　[Pt(BO3)(2)O-2](6-)　chains　along　the　b-axis.　MgO6　octahedra　are　arranged　in　the　form　of　two　dimensional　(2D)　layers.　The　2D　MgO6　layers　are　further　connected　by　the　anionic　[Pt(BO3)2O(2)](6-)　chains　into　the　3D　framework　structure　of　Mg3Pt(BO3)(2)O-2.　The　material　was　experimentally　and　theoretically　characterized　in　regards　to　its　optical　and　spectroscopic　properties.