3-Hy-droxy-2-(4-meth-oxy-phen-yl)-4H-chromen-4-one.

In the title compound, C(16)H(12)O(4), the benzene ring is twisted at an angle of 12.3 (1)° relative to the 4H-chromene skeleton, and an intramolecular O-H⋯O hydrogen bond occurs. The meth-oxy group is almost coplanar with the benzene ring [1.5 (1)°]. In the crystal, inversely oriented mol-ecules are arranged in double (A, A') columns, along the b axis, and are linked by a network of inter-molecular O-H⋯O hydrogen bonds (between A and A') and C-H⋯π contacts (within A or A'). The 4H-chromene cores are parallel within A or A', but make a dihedral angle of 88.6 (1)° between A and A'.

2-(4-Fluoro-phen-yl)-3-hy-droxy-4H-chromen-4-one.

In the crystal structure of the title compound, C(15)H(9)FO(3), inversely oriented mol-ecules form inversion dimers through pairs of O-H⋯O hydrogen bonds. The benzene ring is twisted at an angle of 12.0 (1)° relative to the 4H-chromene skeleton of the mol-ecule. Adjacent 4H-chromene units are parallel in a given column or oriented at an angle of 50.0 (1)° in neighboring, inversely oriented, columns, forming a herringbone pattern.