This paper presents aspects of the coordination chemistry of mono- and divalent manganese complexes supported by the anionic tris(phosphino)borate ligand, [PhBPiPr3] (where [PhBPiPr3] = [PhB(CH2PiPr2)3]-). The Mn(II) halide complexes, [PhBPiPr3]MnCl (1) and [PhBPiPr3]Mnl (2), have been characterized by X-ray diffraction, SQUID magnetometry, and EPR spectroscopy. Compound 2 serves as a precursor to a series of Mn azide, alkyl, and amide species: [PhBP iPr3]Mn(N3) (3), [PhBPiPr 3]Mn(CH2Ph) (4), [PhBPiPr3]Mn(Me) (5), [PhBPiPr3]Mn(NH(2,6-iPr2-C 6H3)) (6), [PhBPiPr3]Mn(dbabh) (7), and [PhBPiPr3]Mn(1-Ph(isoindolate)) (8). The complexes 2-8 feature a divalent-metal center and are pseudotetrahedral. They collectively represent an uncommon structural motif for low-coordinate, polyphosphine- supported Mn complexes. Two Mn(I) species have also been prepared. These include the Tl-Mn adduct [PhBPiPr3]Tl-MnBr(CO)4 (9) and the octahedral complex [PhBPiPr3]Mn(CN tBu)3 (10). Some of our initial synthetic efforts to generate [PhBPiPr3]Mn=Nx species are briefly described, as are DFT studies that probe the electronic viability of these types of multiply bonded target structures.