Mangal Chandi story in Bengal are found in the Chandir geett or Chandimangal Kavya. The two important stories are that of Kalaketu and Dhanapati.
Nidaya, the wife of hunter Dharmaketu, was worried that her husband would marry again as she was unable to give him a child. She offer prayers to Mangala Chandi for a child. One day the goddess in the guise of an old woman appeared in the house of the hunter Dharmaketu and met his wife Nidaya. The pious young woman welcomed the old woman with due respect.
Then Nidaya told the old lady that she was worried that her husband would marry again as she was unable to give him a baby.
Hearing this the Goddess felt pity and offered her medicine against sterility.
In due course of time a son was born to Nidaya and Dharmaketu by the blessing of Goddess Mangala Chandi. Dharmaketu gave up the idea of taking a second wife. The son born to them was named Kalaketu.
Second Story
Dhanapati had two wives Lahana and Khullana. When Dhanapati was out from the house, Lahana, the first wife, used to badly treat Khullana, the second wife.
One day when Khullana was grazing the goats, a goat was lost and she was worried that Lahana would make this into a big issue.
While searching for the missing goat in the forest, she happened to meet five nymphs and told them about the lost goat and her pitiable condition at home.
The nymphs advised her to worship Goddess Mangala Chandi, who is the remover all troubles of human beings.
Khullana then worshipped Goddess Mangala Chandi with utmost devotion. Goddess appeared before Khullana and asked her to ask for a boon. The innocent woman asked the goddess to help her in locating her lost goat.
Goddess Mangala Chandi was moved by the innocence of Khullana and blessed her that she will become the chief of her household and that she will be blessed with a healthy baby.
When Dhanapati returned from his business tour, he came to know about the boon.
Khullana earned the sympathy and love of her husband. Soon they had a son named Srimanta. With the blessing of Mangala Chandi, Khullana was able to create a happy family.