Volatile allylic dihaloboranes have been prepared and characterized by H-1, B-11, C-13, and F-19 NMR spectroscopy and mass spectrometry. The stability (tau(1/2)) of such compounds in dilute CDCl3 solutions depends on the substituents and the halides and ranges from a few minutes (allylic dibromoboranes) to several days (allylic difluoroboranes). Allyldihaloborane etherates were obtained by addition of diethyl ether to the corresponding free allyldihaloborane.