4-Ethynyl-1,2-methylenedioxybenzene at 150 K.

The title compound, C(9)H(6)O(2), contains two moderate C-H.O hydrogen bonds. That involving the terminal alkyne gives rise to chains along the b axis. The other hydrogen bond occurs over a centre of symmetry, leading to dimers. The combination of the two interactions gives rise to rings, each comprising six molecules, which are part of infinite sheets in the bc plane.