| 1. Bhupendranath experienced a significant loss at the age of four when his father died, causing the family to move to his maternal grandparents' home. |
| 2. He endured another tragedy at age 22 with the death of his oldest brother, who had taken over the family responsibilities. |
| 3. His participation in the Brahmo Samaj influenced his beliefs in a caste-less society and opposition to superstitions. |
| 4. He edited the newspaper Jugantar Patrika, closely associating with notable figures like Sri Aurobindo. |
| 5. During World War I, he actively engaged in revolutionary activities in Germany. |
| 6. He presented a research paper on India’s political conditions to Vladimir Lenin in Moscow in 1921. |
| 7. Datta co-founded the Calcutta Tramways Workers’ Union and was deeply involved in organizing labor movements. |
| 8. He contributed to the Progressive Writers’ Association and supported community kitchens during the Bengal Famine of 1943. |
| 9. In 1916, he became the secretary of the Indian Independence Committee in Berlin, serving until 1918. |
| 10. He joined the German Anthropological Society in 1920 and the German Asiatic Society in 1924. |
| 11. At the 1930 Karachi session of the Indian National Congress, he proposed and had accepted a fundamental right for Indian farmers by the committee led by Jawaharlal Nehru. |
| 12. He served as president of the All Bengal Youth Association and chaired annual conferences of the All India Trade Union Congress. |
| 13. He passed the Entrance examination from Metropolitan Institution in 1898. |
| 14. He joined the Bengal Revolutionary Society formed by Pramathanath Mitra in 1902. |
| 15. He was sentenced to one year's imprisonment in 1907 and released after eleven months. |
| 16. He went to America on 16 August 1908. |
| 17. He graduated from New York University in 1912. |
| 18. He visited Europe in 1914 and Russia in 1921. |
| 19. He returned to India in 1925. |
| 20. He was the youngest of seven siblings, with his eldest brother being Narendranath Datta, who became the renowned Swami Vivekananda. |
| 21. He chaired the reception committee for the Socialist Youth Congress held on 27 December 1927 in Calcutta, where he drew attention to Marxism. |
| 22. He sent a personal appeal to Jawaharlal Nehru during the late-1920s labor unrest in Bombay's textile mills and played a pivotal role in setting up the Meerut Defence Fund. |
| 23. During the Bengal Nagpur Railway strike of 1927, he set up camp in Kharagpur to support the workers. |
