The derby was postponed owing to the fragile political situation in the state. It was originally slated to take place on December 22.
On Thursday, ATK acquired majority stake in Mohun Bagan and the green and maroon side will join hands with ATK to play in the ISL from next season.
The RPSG Group, which owns and runs two-time ISL champions ATK, became an 80 per cent majority shareholder with Mohun Bagan owning the remaining 20 per cent shares.
The merged club will come into existence from June 1, 2020 and will compete in the ISL 2020-21, along with other important competitions in the All India Football Federation (AIFF) calendar.
It was a momentous occasion for Mohun Bagan who were looking for a sponsor and wanted to participate in the ISL, which has been accorded the status of the country's top league.
Former Mohun Bagan players and sections of their supporters hailed the merger, saying they wanted to see their club feature in the premier league of India and get a chance to represent the country at the continent forum with the AFC Champions League playoff slot up for grabs for those who top the ISL table at the end of the league.
In the I-League, Mohun Bagan are at the top of the heap with 14 points from seven matches and stand a chance to win the competition and end on a high. Under Spanish coach Kibu Vicuna, Mohun Bagan have looked a well oiled machine winning four games and losing just one and are also on a five-match winning streak.
They were held by second-placed Punjab FC to a 1-1 draw away in their last outing and would look to get back to winning ways against East Bengal who are struggling.
Coached by Spaniard Alejandro Menendez, the red and golds lost 1-3 at home to Gokulam Kerala FC in their last tie making it two losses in a row and drawing the ire of the fans who heckled their principal investors Quess CEO Sanjit Sen and COO Biswajit Chatterjee after the game at the Kalyani Municipality Stadium.
They had lost 0-1 to Churchill Brothers too in Goa, thus languishing in sixth position in the 11-team points table with eight points from six matches.
A win for Mohun Bagan in the Kolkata derby can take them six points clear at the top and open a nine-point gap with East Bengal, and the Mariners will look to extend their rich vein of form and add to the celebrations of the merger.
( With inputs from IANS )