The polycrystalline samples of Ba 5 RTi 3 Nb 7 O 3 0 (R = Dy, Sm) complex tungsten-bronze-type compounds were prepared using a high-temperature solid-state reaction technique. Preliminary X-ray structural analysis of the compounds suggests the formation of single-phase compounds in an orthorhombic crystal system at room temperature. Dielectric studies as a function of frequency and temperature show that these compounds have diffuse phase transition with different diffuseness characteristics.