6-Nitro-1,3-benzdioxin is orthorhombic,Pbca,a=7.278(4),b=19.292(3),c=10.978(1) Å,Z=8. The structure was solved by direct methods from data collected at room temperature on an Enraf-Nonius CAD4 diffractometer and refined by least squares to a finalRvalue of 0.041 using 725 reflections. Some parameters associated with the heterocycle are torsion angle (CAr)O-C-O-C(CAr) 69.1(4)°; bond lengths CAr-O 1.362(3), (CAr)O-C 1.434(5), (CAr.O)C-O 1.377(5), O-C(CAr) 1.431(5), C-CAr1.501(5) Å; bond angles CAr-O-C 113.5(3), O-C-O 111.5(3), C-O-C(CAr) 110.3(3), O-C-CAr109.9(3)°;Hax⋯Hax2.52