Ba5NdNi1.5Nb8.5O30 tungsten bronze ceramic was prepared by the conventional solid-state reaction. Rietveld analysis revealed that this ceramic crystallizes in space group p4bm. The dielectric and magnetic properties of Ba5NdNi1.5Nb8.5O30 were investigated in relation to its structure. A broad dielectric constant peak at 293 K was observed in the dielectric spectrum of Ba5NdNi1.5Nb8.5O30, suggesting a diffused normal ferroelectric transition. A modified Curie Weiss law was used to characterize the diffuseness of the phase transition with a frequency of 1 MHz and the diffusivity gamma was measured to be 1.102. The dielectric properties originate from the different crystal structures governed by the occupancy of cations at A(1) and A(2) sites. Ba5NdNi1.5Nb8.5O30 ceramic presents a weak antiferromagnetic interaction and the calculated effective moment is 4.77 mu B/f.u. (C) 2012 Elsevier B.V. All rights reserved.