A new family of di(1-oxo/thioxoperhydro-1λ⁵-[1,3,2]diazaphospholo[1,5-a]pyridine-1-yl) (4-substituted phenyl) boronates (4a–j) has been synthesized in a two-step process. A reaction of (±)-piperidin-2-yl-methanamine (1) phosphoryl/phosphorothioyl chloride in the presence of triethylamine in dry tetrahydrofuran formed the intermediate monochloride (2), which on condensation with psubstituted phenylboronic acids (3a–j) afforded the titled compounds (4a–j). They were characterized by elemental, IR, ¹H, ¹³C, ³¹P NMR, and mass spectral analyses. All these compounds showed moderate to high antiosteoclast and osteoblast activity.