The title compound2-p-methyloxyphenyl-3a-（2-phenyl-1,2,3-triazole-4-yl）-3,4- dihydro-1,2,4-oxa-diazolo[4,5-d][1,5] benzothiazepine （C31H25N5O2S, Mr = 531.63） has been synthesized and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic, space group P1^- with a = 10.888（2）, b = 15.115（3）, c = 16.702（3）A, α = 99.90（3）, β = 95.21（3）, γ = 100.41（3）°, V = 2642.1（9） nm^3, Dc = 1.336 g/cm^3, Z = 4, F（000） = 1112, μ = 0.162 mm^-1 ,λ（MoKα） = 0.071073 nm, R = 0.0357 and wR = 0.1126 for 10620 observed reflections with I 〉 2σ（I）. X-ray analysis reveals that the molecular backbone consists of a tricyclic system with the central seven- membered ring in a twisted boat-like conformation.
