Thin film capacitor structures in which the dielectric is composed of superlattices of the relaxors [0.2Pb(Zn1/3Nb2/3)O3 – 0.8BaTiO3] and Pb(Mg1/3Nb2/3)O3 have been fabricated on MgO {100} substrates by Pulsed Laser Deposition. Structural studies show dielectrics to be 100% perovskite, with strong chemical distinction between individual relaxor layers. The dielectric properties of the superlattices were investigated as a function of periodicity. Significant enhancement of the dielectric constant was observed in relatively fine-scale superlattices, consistent with previous studies. However, unlike previous work, in these relaxor superlattices dielectric enhancement is not associated with increased loss. Rather tan δ is low across the entire superlattice series. Polarisation measurements as a function of temperature suggest that the observed enhancement in dielectric constant is associated with the onset of coupled behaviour. The thickness of the individual layers in the superlattice at which coupled functional behaviour becomes apparent is ∼10nm and is comparable to that found in literature for coupled structural behaviour.