The 6,8-dimethyl-cis-2-vinyl-2,3,4,5-tetrahydro-1H-benzo[b]azepin-4-ol (2a) (Chemical formula C14H19NO) and 8-chloro-9-methyl-cis-2-(prop-1-en-2-yl)-2,3,4,5-tetrahydro-1H-benzo[b]azepin-4-ol (2b) (Chemical formula C14H18ClNO) were prepared via the reductive cleavage of the bridged N-O bond of the corresponding 1,4-epoxytetrahydro-1-benzazepines. The X-ray powder diffraction patterns for the new compounds were obtained. The compound 2a was found to crystallize in an orthorhombic system with space group Pmn2(1) (No. 31), refined unit-cell parameters a = 19.422(6) angstrom, b = 6.512(3) angstrom, c = 9.757(4) angstrom and V = 1234.0(5) angstrom(3). The compound 2b was found to crystallize in a monoclinic system with space group P2(1)/m (No. 11), refined unit-cell parameters a = 17.570(4) angstrom, b= 8.952(3) angstrom, c = 14.985(4) angstrom, beta = 101.66(2)degrees, and V = 2308.3(9) angstrom(3). (C) 2011 International Centre for Diffraction Data. [DOI: 10.1154/1.3656975]