Four types of oxides, ATiM 2 O 8 (A: Mg, Zn; M: Nb, Ta) were prepared by high-temperature solid-state reaction. MgTiNb 2 O 8 , ZnTiNb 2 O 8 and ATiTa 2 O 8 had rutile-type, α-PbO 2-type and trirutile-type structures, respectively. The crystal structures of these compounds were refined based on the synchrotron X-ray powder diffraction data with the following R-factors: R wp = 4.34% and R p = 2.21% for MgTiNb 2 O 8 ; R wp = 2.19% and R p = 1.52% for ZnTiNb 2 O 8 ; R wp = 9.03% and R p = 6.31% for MgTiTa 2 O 8 ; and R wp = 5.70% and R p = 4.16% for ZnTiTa 2 O 8. Their lattice parameters were a = 4.69585(8) and c = 3.04260(6) Å for MgTiNb 2 O 8 ; a = 4.67138 (6), b = 5.65916(7) and c = 5.00745(6) Å for ZnTiNb 2 O 8 ; a = 4.6876(2) and c = 9.1385(3) Å for MgTiNb 2 O 8 ; and a = 4.6987(7) and c = 9.1296(1) Å for ZnTiTa 2 O 8. The optical band gap for these compounds ranged from 2.98 to 3.15 eV and every compound exhibited a small amount of photocatalytic activity for phenol decomposition under UV light irradiation. However, no photocatalytic activity was observed under visible light irradiation. The dielectric constants for these compounds were between 25 and 125 at a temperature range of room temperature to 400°C.