The reaction of a series of tripodal ligands, H 3 L 1,2 and L 3–6 , with [M(PPh 3 ) 2 Cl 2 ] (M=Ru, Os) affords a family of coordination cage compounds of the type [M III L 1,2 ] (1–4) or [M II L 3–6 ](BPh 4 ) 2 (5–12). The Schiff base ligands (H 3 L 1 , L 3 , L 5 ) have been synthesized by condensation of tris(2-aminoethyl)amine with salicylaldehyde, pyridine-2-aldehyde and 1-methyl-2-imidazolecarboxaldehyde. These ligands were further reduced and subsequently methylated to form the new ligands (H 3 L 2 , L 4 , L 6 ). Single crystal X-ray diffraction studies of 1 and 2 show that the tripodal ligand wraps around the metal center as a hexadentate ligand to form a cage. All the synthesized compounds have been thoroughly characterized by ESI-MS, FT-IR, UV–Vis and NMR spectroscopic methods. To the best of our knowledge, this is the first ever report of osmium complexes with tris(2-aminoethyl)amine based tripodal ligands. DFT calculations were performed to obtain geometry optimized structures of all the other complexes (3–12).