Adoor Diocese was part of Kottarakara - Kollam diocese which covered a larger area from Achenkoil river (North) to Kulasekharam (South) without having headquarter of its own. In 1957, Rt. Rev. Thomas Mar Athanasius Episcopa bought 60 cents of land at Adoor near government high school and constructed new Aramana there.
The members of Adoor Immanuel Marthoma Church, Mr. K.V. Oommen Kottaykattu and Mr. P.I. Pothen Plamuttil, are to be specially acknowledged for their valuable support at that time. Though Thomas Mar Athanasius Episcopa served only for a short time and was shifted to new diocese as per the arrangement of the church, Thirumeni's vision and enthusiasm gifted a centre for the functioning of the diocese. The following are the chronological Episcopal succession of the diocese.
During Thirumeni’s tenure Adoor- Mavelikara Diocese was divided and renamed as Adoor Diocese. He Initiated projects such as Tharavadu, Swanthanam, Chiraku, Theertham, Thaibooso, Bala samajam. am Kalayapuram Mar Thoma Residential School & Mar Thoma Gurukulam Manakkala for dedicated children
Adoor – Thumpamon diocese was divided and renamed as Adoor – Mavelikkara and Chengannur – Thumpamon. At this time, the financial crisis of the diocese was solved and the diocese became self-dependent. Roofing of the convention nagar was done. Nursing school was started at St. Thomas Mission hospital, Kattanam