In this work, coordination compounds of Co (II) with derivatives of dihydro-4H-3,1-benzoxazines were synthesized by a chemical method and their composition, structure, and physicochemical properties were studied. ... According to the data of elemental analysis and analysis for metal, the obtained complex compounds have the composition ML2, where M is metal, L are ligands: 2- [2-hydroxyphenyl] -4,4-diphenyl-1,2-dihydro-4H-3,1benzoxazine (L1), 2- [2-hydroxy-5-nitrophenyl] -4,4-diphenyl-1 , 2-dihydro-4H-3,1-benzoxazine (L2), 2- [2hydroxynaphthyl] -4,4-diphenyl-1,2-dihydro-4H-3,1-benzoxazine (L3), 2- [ 2-hydroxynaphthyl] -4,4-diethyl-1,2dihydro-4H-3,1-benzoxazine (L4). The structure and properties of the obtained complex compounds were studied by IR spectroscopy. According to IR spectroscopy data, it was found that in all complex compounds, the ligand participates in the open azomethine form; coordination with the metal atom involves two oxygen atoms and a nitrogen atom of the azomethine fragment of the ligand. It was found that the ligand in the complex performs a tridentate chelate-bridging function. The structure of complex compounds of cobalt with derivatives of benzoxazines is proposed.