Dielectric response of Bi 2 (Zn 1/3 Nb 2/3 ) 2 O 7 , BiZN, ceramic materials and thin films were examined, for the first time, compared directly using terahertz (THz) spectroscopy. In the preparation of the ceramic materials, the two-step process exhibits a marked advantage over the one-step process in that the ceramic material's characteristics are relatively insensitive to the sintering parameters. The ceramic materials can achieve high density (7.2 g/cm 3 ), large dielectric constant (K=67), high quality factor (Q×f≅80,000 GHz) and small temperature coefficient of resonance frequency (τf≅−6 ppm/°C), when processed at optimized sintering temperature (1050°C, 4 h). Crystalline BiZN thin films, can be easily obtained when the films were in-situ deposited at high enough substrate temperature 450–600°C (30 min). The dielectric constant of BiZN thin films in THz frequency regime, ε′f·THz=32, is markedly smaller than the ε′b·THz value of BiZN bulk materials, and the quality factor of the thin films is less than 20% of the bulk materials.