The synthesis and the study of X-ray and dynamic 1H-NMR of new N,N-dimethyl carbamoyl 5-aryloxytetrazoles. The first report of unusually high rotational energy barrier about CN bond in the moiety of urea group. The barrier to rotations were studied by both dynamic 1H-NMR and computation at level of B3LYP/6-311++G**. The first report of unusually low rotational energy barrier about CN bond of OCN (2-tetrazolyl) by B3LYP/6-311++G**.