The suitability of Tl 2Ba 2CaCu 2O 8 (Tl-2212) and MgO for growing SIS trilayers by metal-organic chemical vapor deposition (MOCVD) is examined. Low temperature (500°C) epitaxial (100) MgO film growth on (110) LaAlO 3 by MOCVD using Mg(dpm) 2 (dpm=2.2.6.6-tetramethyl-3,5-heptanedionate) is demonstrated. Tl-2212 does not decompose under these MgO growth conditions, although decomposition occurs at lower O 2 partial pressures. To form trilayer structures. BaCaCuO(F) films are first grown on (110) LaAlO 3 by MOCVD using Ba(hfa) 2 · mep (hfa=1,1,1,5,5,5-hexafluoropentane-2,4-dionate; mep=2,5,8,11,14,17-hexaoxanonadecane), Ca(hfa) 2 tet (tet=2,5,8,11,14-pentaoxapentadecane) and Cu(dpm) 2 precursors and are then post-annealed in the presence of bulk Tl 2Ba 2CaCu 2O N to form Tl-2212. MgO is then deposited by MOCVD. Finally, a top TBCCO layer is grown by MOCVD and subsequent Tl 2O anneal to complete the trilayer. Both of the TBCCO layers are highly oriented, while the MgO layers are largely polycrystalline due to the rough underlying Tl-2212. Both TBCCO layers are superconducting ( T c ∼ 105 K).