In the title compound, C12H10O2, the molecules are stacked and form layers
parallel to the (101) planes. Each molecule consists of three six-membered
rings which are not strictly coplanar. The dioxine ring adopts a half-chair
conformation with an angle of 55.2(4)degrees between the (O1, C12, C11) an
d (C12, C11, O2) planes. The crystal arrangement is stabilized by van der W
aals forces.