In October of 1948, right after World War 2, Pope Pius XII appointed him as the Apostolic Administrator of Arabia after the resignation of Msgr.
[3] On 25 December 1949, he was nominated as Titular Bishop of Dium and The Apostolic Vicar of Arabia.
[4] Magliacani was quick to assess the situation following World War 2 and fulfilled the urgent requirement for churches and personnel in Somalia, Yemen, and Bahrain; by this time in the 1950s, as the nations in the Persian Gulf were striking oil, Magliacani saw the rising prominence of the mission in Bahrain.
During these years, events in South Yemen were taking a turn for the worse after the British left Aden in 1967, and Communists soon took control.
[6] On 4 November 1969, Irzio Luigi Maglacani resigned as Apostolic Vicar of Arabia.