AbstractA new multicage compound [(Me)2EtNH][Mn(N3)3] (Me = methyl, Et = ethyl) with a perovskite-related structure has been synthesized. The manganese(II) cations are bridged by end-to-end (EE) azide anions to form three-dimensional cages with the N,N-dimethylethylammonium cations residing in the cavities of the [Mn(N3)3]nn− cages. The compound has been characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, second-harmonic generation, and magnetic measurements. The second-harmonic generation results support its noncentrosymmetric polar crystal structure. Magnetic susceptibility measurements show antiferromagnetic interactions among the MnII ions.