Encouraged by the liberal spirit reigning in the campus, Bhupen brought together his own group of college-mates interested in social work, raising funds for the poor by offering manual labour, gymnastics, study sessions for the Gita and essays of contemporary thinkers.

Invited by his friend Hemanta Kumar Sarkar, Bhupen went to Krishnagar and spent a few days in the company of Subhas Chandra Bose, the future "Netaji".

Arun Chandra Guha wrote: "The police had somehow got information that behind the facade of relief work, Jatin and other workers were forging a powerful revolutionary organisation".

[4] Bhupen was to know later that during the flood relief, at Kalinagar in Medinipur, Atulkrishna Ghosh, Amarendra Chatterjee, Jadugopal Mukherjee and others brought together, under the moral and spiritual caution of Bagha Jatin, the various branches and sub-groups of the secret societies in order to create the rising Jugantar, which was more a concerted movement than a party.

[5] After returning to Daulatpur, Bhupen learnt from his college mate Gopaldas Majumdar that Bagha Jatin was soon leaving his business as a contractor in order to go back to Kolkata.

"[10] In spite of such a hectic social programme, in March 1915 Bhupen passed his Intermediate Examination securing very high marks, with distinctions for the quality of his Bengali and English prose.

Stunned by the leader's sudden death, whereas his top-ranking associates felt helpless and absconded, Bhupen stepped forward to remind them that a revolution could not die with the leader's death:[citation needed] "Bhupendra Kumar Datta remained the sole moving worker to maintain the links and collect money," admitted Arun Chandra Guha.

Having the latter's promise that, if the people responded well, he would convert the Party into free India's Republican Parliament, Bhupen went to Pondicherry to consult Sri Aurobindo about the future of the Jugantar.

After Gandhi's failure, the Jugantar sided Deshabandhu Chittaranjan Das in his Swarajya programme as an antidote: by observing overtly, all over India, the eighth anniversary of Bagha Jatin's death, on 9 September 1923, they intimated their intention to follow their own conviction.

In 1946 his collection of essays, Indian Revolution and the Constructive Programme appeared with a foreword by Dr Rajendra Prasad, the first president of future independent India.

Among several reports of his action, it was learnt that on 7 March 1949 when Prime Minister Liaquat Ali Khan, while claiming support from Quaid-i-Azam declared before the Constituent Assembly that Pakistan was founded with the Muslims’ wish to live the teachings and the tradition of Islam, one of the members, Birat Chandra Mondal reminded that Muhammad Ali Jinnah had "unequivocally said that Pakistan will be a secular State."

On 28 March 1971, at the onset of Bangladesh Liberation War, Pakistani military junta tortured Dhirendranath Datta to death in Comilla.

During his absence, on 9 September 1947, an imposing Bagha Jatin memorial week was observed in West Bengal, and the former Jugantar members had chosen Bhupen for writing an authentic biography of their leader.

Encouraged by the enthusiasm of a young researcher, Bhupen passed on to him the lifelong notes and reflections he had accumulated, accompanied him to interview most of the important associates of Bagha Jatin and opened before him the access to the archives in India.

[citation needed] His first-hand knowledge of events was of a great lesson in historical research : while comparing oral statements with files in the archives and, at times before apparent contradictions, his spirit of synthesis and intuition helped to determine their complementary character.

"Simple, unostentatious but erudite, Bhupendrakumar, with his well-built physique, serious but candid countenance, sparkling eyes and friendly smile, impresses one as an ascetic missionary mellowed by love for man.

He is a firm believer in reason, science and progress, and has no patience with casteism, regionalism and communalism, nor with institutional religion that creates isolation and alienation," wrote Kamala Das Gupta.