The Chittagong armoury raid was carried out on 18 April 1930. Kalpana joined the "
Indian Republican Army, Chattagram branch," the armed resistance group led by Surya Sen, in May 1931. In September 1931, Surya Sen entrusted her, along with
Pritilata Waddedar, to attack the European Club in Chittagong. A week before the attack, she was arrested while carrying out reconnaissance of the area. She went into hiding after her release on bail. On 16 February 1933, the police encircled their hiding place in Gairala village. During this raid, Surya Sen was arrested, but Kalpana managed to escape. To free Surya, she tried to bomb the jail but failed. Kalpana was finally arrested on 19 May 1933. In the second supplementary trial of the Chittagong armoury raid case, Kalpana was sentenced to
transportation for life. She was released in 1939. == Later life ==