The  birth of Campion Old Boy's Association could be tracked back to the 13th School Day in 1946. The Principal during that period, Fr.Hession, had accepted the suggestion of Fr.Shields and expressed the need for an alumini association. so the same year on December 1st, the feast of blessed Edumund Campion, the Campion Old Boy's Association ( COBA) was founded with Fr.Shields as the President and Mr.  Joseph Rodrigues as the Secretary. The first reunion day of the association was held on the 31st July 1946, on the feast of St.Ignatius of Loyola. In 1948,Rev.Fr.Shields left for Malta and Rev. Fr.Merrifield took over as the president of the Association. He was to become the longest serving President from 1948 to 1972 for a record period of 25 years.

The sliver Jubilee of COBA on 19th September, 1971. The year 1972 was the Golden Jubilee of Fr. Merrifield. The Reunion Day the year was held on 8th October, the President's 74th birthday. it was a great day for the many OBs who attended, fro apart from the usual celebrations, a special function in the evening under the Chairmanship of Fr. Tamby felicitating Fr. Merrifield was held. The same year the Jesuits were to leave Campion and the school was to be handed back to its owner, the Bishop of Trichy.

The Golden Jubilee of COBA was celebrated on the 27th and 28th, December 1997. Today, in the new millennium, COBA as an association, continues to grow, especially with the infusion of a lot young blood, bubbling with enthusiasm and being spontaneous in their efforts for the growth of the Association.