The extremist leader of the Indian National Congress was Bipin Chandra Pal.

Bipin Chandra Pal was a prominent Indian nationalist and one of the key leaders of the Indian National Congress during the early 20th century. He played a crucial role in the Indian independence movement and was known for his radical ideas and strong anti-British stance.

Key Points:
- Early Life: Bipin Chandra Pal was born on November 7, 1858, in Sylhet (now in Bangladesh). He came from a Brahmo Samaj background and was influenced by the teachings of his father, who was a follower of Keshab Chandra Sen.
- Role in the Indian National Congress: Bipin Chandra Pal joined the Indian National Congress in the late 1880s and became one of its prominent leaders. He was part of the moderate faction initially but later became associated with the extremist faction of the Congress.
- Extremist Ideology: Pal believed in aggressive nationalism and advocated for the complete independence of India from British rule. He firmly believed in the use of Swadeshi (boycott of British goods) and Swaraj (self-rule) as effective tools to achieve freedom.
- Partition of Bengal: Bipin Chandra Pal actively participated in the anti-partition movement in Bengal in 1905. He played a crucial role in mobilizing people against the British decision to divide Bengal on communal lines. He gave powerful speeches and wrote extensively to raise awareness about the issue.
- Role in the Swadeshi Movement: Pal played a pivotal role in the Swadeshi Movement, which aimed to promote Indian industries and boycott British goods. He traveled extensively across the country, inspiring people to adopt Swadeshi practices and to resist British economic exploitation.
- Legacy: Bipin Chandra Pal's contributions to the Indian independence movement were significant. He was a powerful orator and writer who used his skills to galvanize the masses and promote the cause of nationalism. He is remembered as one of the key leaders of the extremist faction of the Indian National Congress.

In conclusion, Bipin Chandra Pal was an influential leader of the Indian National Congress who espoused extremist ideologies and played a crucial role in the Indian independence movement. His strong anti-British stance and advocacy for Swadeshi and Swaraj made him a prominent figure in the fight for freedom.