In the present study the basic set B3LYP/ LanL2Dz level used and investigated 3d transition metal monoborides utilizing the density functional approach. The dimers, the lowest spin state, bond length, vibrational frequencies are calculated. These dimers' cation and anion are also investigated. It was discovered that the ionization potential of these dimers is substantially higher than their electron affinities. The range of electron affinities for 3d transition metal monocarbides is the broadest and the narrowest for 3d transition metal mononitrides. Ionization potential ranges are greatest for 3d transition metal monoborides and narrowest for 3d transition metal monocarbides as it was studied by earlier researchers. In this article monoborides spin multiplicity, vibrational frequencies and their bond length studied.