Bis(p-methoxyphenyl)-2-methyl-8-hydroxyquinoline borolactone (I) is orthorhombic, space group Pbca, with a 1.1741(5), b 1.6104(3), and c 2.1066(5) nm; Z = 8, R = 0.043. Bis(p-methoxyphenyl)-8-hydroxyquinoline borolactone (II) is monoclinic, space group P21/a, and a 1.0008(1), b 1.3956(2), c 1.3617(3)nm, and b 100.15(1)? Z = 4, R = 0.089. The structures of the 2 compounds were solved by direct method. The atoms of B, C(39), C(37), N and O(3) form a chelate ring with coordinated bond between B and N atoms. Dihedral angle between two benzenes is 57.8?for I and 95.7?for II. The bond order and charge d. from quantum chem. calculation indicate the covalent nature of the bonds involving B atom. Atomic coordinates are given.

Key words: CRYSTAL STRUCTURE, CALCULATION, QUANTUM CHEMISTRY, BORIC ACID ESTERS, HYDROXY QUINOLINES, ELECTRONIC STRUCTURE