Mesit-yl(2,4,6-trimeth-oxy-phen-yl)borinic acid.

In the title mol-ecule, C(18)H(23)BO(4), the dihedral angle between the least-squares planes of the aromatic rings is 84.88 (3)°. The B atom deviates by 0.202 (1) Å from the least-squares plane of the mesityl ring. All of the meth-oxy groups are approximately coplanar with the 2,4,6-trimeth-oxy-phenyl ring, whereas the BOH group is twisted with respect to it by 19.5°. The borinic OH group is engaged in an intra-molecular O-H⋯O hydrogen bond with one of ortho-meth-oxy groups. The mol-ecular structure is stabilized by weak C-H⋯O contacts. In the crystal, mol-ecules are linked by weak C-H⋯O and C-H⋯π inter-actions, generating a three-dimensional network.