Only child, posthumous, of Abhay Charan Mukherjee, youngest brother of Holy Mother, her life inseparably intertwined with that of Holy Mother after the demise of the Master. Born on 26.1.1900 at Jayrambati. Her mother, Surabala, having lost mental balance due to several mishaps, Holy Mother took charge of her and she addressed her as “Mother”. Before and after her birth the Master had indicated to Holy Mother that this girl represented “Yogamaya” and was to be the earthly tie to keep her ever-soaring thoughts on a material plane. She and her mother were permanent constituents of Holy Mother’s life till a few days before her passing. They accompanied her everywhere, she took every care of Radharani, catering to her every whim rational or not. Married to Manmathanath Chatterjee of the Tajpur zamindar family with pomp and ceremony on 10.6.1911. The couple were disciples of Holy Mother. Radharani went on pilgrimages with Holy Mother. After her marriage she displayed signs of mental instability causing Mother much anxiety and worry, besides being an unsettling factor in her life. Son born to Radharani some months before Holy Mother’s passing. After her passing Manmatha refused to accept her and married again, though he occasionally visited Radharani at Jayrambati and pressed her for money. At this time a daughter, Nirmala, was born to her, the son having died earlier. Having contracted tuberculosis she was sent to Varanasi for treatment but knowing her end to be imminent she insisted on returning to Jayrambati where she spent her last days in Holy Mother’s room in her new house and died there on 23.11.1940. The constant sacred company of Holy Mother had fostered a spirit of detachment in her leading to an attitude of indifference to worldly matters (Udbodhan, 42.12.744).