On 1985, the first Archbishop of Palo, Cipriano V. Urgel died. Dean was appointed as the new Archbishop of Palo on October 12, 1985 and installed on 13 December of the same year. Before he was installed as the second Archbishop of Palo, he was appointed as Apostolic Administrator of his hometown, the
Diocese of Calbayog, on 28 October 1985 after the resignation of Bishop Sincero Lucero, the seventh
Bishop of Calbayog. He received the pallium from the hands of
Pope John Paul II on the Solemn Ceremony on the Feast of Sts. Peter and Paul at St. Peter's Basilica on 29 June 1986. During his incumbency, he founded the St. John the Evangelist School of Theology in 1988 and constructed the Archdiocesan Chancery during the 1990s. He was a former member of the following Episcopal Commissions: • Liturgy • Family Life • Social Action • Doctrine of Faith • Special Committee on Finance. He was elected as member of the administrative board (now permanent council) from 1986 to 1988 and re-elected from 1989 to 1991. In 1993, he was elected chairman of the Commission on Doctrine of Faith, and member of the Commission on Clergy. ==Retirement==