The three assembly constituencies are Bagda in North 24 Parganas district, Ranaghat-South in Nadia district and Maniktala in Kolkata.

However, Left Front insiders said the decision to leave Raiganj assembly constituency in North Dinajpur district for the Congress has been taken as part of the seat-sharing agreement between the two parties for the recently concluded Lok Sabha elections.

Of the three assembly constituencies for which the Left Front has announced candidates, CPI-M will contest from Ranaghat-South and Maniktala, while the All India Forward Bloc will contest from Bagda. CPI-M candidates from Ranaghat-South and Maniktala are Orinda Biswas and Rajib Majumdar respectively, while the Forward Bloc candidate from Bagda is Gauraditya Biswas.

The ruling Trinamool Congress announced the names of candidates for all four constituencies during the day. BJP has not yet announced candidates for the by-election.