The Bengal Renaissance in the first half of the 19th century led to the beginning of the Brahmo reform movement, started by Raja Rammohan Roy based on the concepts of monotheism and ethical precepts. Debendranath Tagore and Keshab Chandra Sen carried out reform activities but differences grew among them which led to the schism of the Brahmo Samaj- Adi Brahmo Samaj and Brahmo Samaj of India. Furthermore, the marriage controversy between the daughter of Keshab Chandra Sen, Sunity Devi, and Maharaja of Cooch Behar, Nripendra Narayan led to the second schism of Brahmoism. Those who objected to the marriage formed the Sadharan Brahmo Samaj and Keshab Chandra and his followers formed Nababidhan Brahmo Samaj. Nripendra Narayan declared himself a Brahmo and contributed a lot to modernizing Cooch Behar. Sunity Devi played a vital role in spreading the Nababidhan faith and the all-around development of this native State. Gajendra Narayan and Sabitri Devi also took the leading role in propagating Brahmoism. This reform movement in Cooch Behar resulted in the significant aesthetic, social and religious development of the State. But due to the gradual revival of Hindu culture and practices in the royal family after the death of Nripendra Narayan, Brahmoism lost its influence. Only the people of the upper strata of the society were influenced by the ideology of the Brahmoism, ordinary masses remained outside the orbit of the movement. But it is also true that modern Cooch Behar owes much of its modernization due to the Brahmo reform movement.