President Pratibha Patil, Vice President Hamid Ansari, Prime Minister Manmohan Singh and BJP leader L K Advani said in his death, the nation had lost an eminent statesman who had earned the unique distinction of being the longest serving Chief Minister.
"During his political career he displayed his abilities as a leader of the people, an able administrator and an eminent statesman," Patil said in her condolence message.
Vice President Ansari said the sagacity and leadership of the former West Bengal Chief Minister "at both the state and national levels have been a source of inspiration and guidance."
Describing 95-year-old Basu as a powerful regional voice in the national political scene, the Prime Minister said he had turned to the veteran Marxist leader on many occasions for his advice on important issues and the response was always pragmatic.
"In a political career spanning more than six decades, the veteran communist leader steered his party to power in West Bengal, leaving a legacy of uninterrupted rule by the Left Front that he forged through his leadership and legendary skills in building consensus," he said.
Advani, who was in Mumbai, said the late Marxist was among the greats. "He was a stalwart... a great leader".
While the Congress said Basu was one of the country's "worthiest sons", BJP said he was one of the tallest contemporary leaders of Indian politics.
In a condolence resolution, the CPI(M) said its veteran leader was a Marxist who neither wavered in his convictions nor was dogmatic in his approach, becoming a source of inspiration for the Left movement in the country.
The party Polit Bureau said Basu, who joined the Communist Party in 1946, played a significant role in the growth of the party in Bengal and became a symbol of the Left, democratic and secular forces in the country.
Communist Party of India (CPI) leader A B Bardhan said Basu was "fought to the end. We express our heartfelt sadness on his demise".
Senior BJP leader and leader of opposition in Rajya Sabha Arun Jaitley said Basu was a man "committed to the service of his people, his ideology and a sense of idealism".
Recounting his close initmacy with Basu, Finance Minister Pranab Mukherjee said, "He was a towering personality and perhaps in contemporary politics, there was no other personality as much charismatic as he was".
Mukherjee also recalled the contribution of Basu in formation of the first UPA government supported by Left in 2004. "In fact, he was an architect of the first UPA government in 2004, which was supported by the Left parties from outside".
Home Minister P Chidambaram said Basu "strode like a colossus on the Indian political scene for several decades. He was a great patriot, a great democrat and a great source of inspiration.
External Affairs Minister S M Krishna, who was in Kathmandu, said, "The country has lost a steadfast champion of the causes of underprivileged