Alpha alumina (α-Al2 O3 ) are inert materials with outstanding thermal, chemical and mechanical stability. Herein, we fabricate porous single-crystalline (PSC) α-Al2 O3 monoliths at centimeter scale to endow them with high catalytic activity while maintaining their stability. We reduce PSC α-Al2 O3 monoliths to create oxygen vacancies in lattice and stabilize them by the ordered lattice to construct unsaturated Al-O coordination structures for enhancing the catalytic activity. The generation of oxygen vacancy at 18e wyckoff position contributes to the unsaturated Al-O coordination. As a case study, we demonstrate the outstanding performance with conversion (≈34 %) and selectivity (≈95 %) toward non-oxidative dehydrogenation of ethane to ethylene at 700 °C. We achieve the outstanding performance without obvious degradation even after a continuous operation over 1000 hours at 700 °C.