Basu, also the state tourism minister, was the founder president of the group and Ghosh, Trinamool MP, was its general secretary. She left the theatre forum on Thursday after which Basu also resigned.
"We could not do whatever we wanted to do and so there is no point in staying here," Ghosh said.
Playwright and director Debesh Chattopadhyay had resigned from Natya Swajan on Wednesday. In the recent past, other members like joint secretary Anish Ghosh, vice-president Manish Mitra and member Ashis Chattopadhyay have also quit the body, throwing questions on its survival.