Soon, she joined the Chhatri Sangha (Women Students Association), a semi-revolutionary organization in which Bina Das and Pritilata Waddedar were also active members.

[5] Kalpana joined the "Indian Republican Army, Chattagram branch," the armed resistance group led by Surya Sen, in May 1931.

[7] In the second supplementary trial of the Chittagong armoury raid case, Kalpana was sentenced to transportation for life.

[citation needed] Kalpana Datta graduated from the Calcutta University in 1940 and joined the Communist Party of India.

[8] She wrote an autobiographical book in Bengali "চট্টগ্রাম অস্ত্রাগার আক্রমণকারীদের স্মৃতিকথা" which was translated into English by Arun Bose & Nikhil Chakraborty with a preface by her husband Com.

[9][10] In 1946, she contested in the elections for the Bengal Legislative Assembly as a Communist Party of India candidate from Chittagong but could not win.