The year 1975 turned out to be the first most eventful year for Vani since she won her first National Film Award for Best Female Playback Singer for the songs she rendered in the film "Apoorva Raagangal". The songs "Ezhu Swarangalukkul" and "Kelviyin Nayagane" made her popularity soar to heights and she became known as the singer who would always get selected to sing difficult compositions. She was flooded with singing offers from all the top rated music composers including M. S. Viswanathan, Kunnakkudi Vaidyanathan, Sankar Ganesh, V. Kumar, K. V. Mahadevan, G. K. Venkatesh and Vijaya Bhaskar. In 1977, she first recorded her voice for Ilaiyaraaja's composition in the film "Bhuvana Oru Kelvi Kuri". She won her first Tamil Nadu State Film Award for Best Female Playback for the song "Naane Naana" composed by Ilaiyaraaja for the film "Azhage Unnai Aarathikkiren" (1979). With Ilaiyaraaja, Vani went on to record many popular songs in the 1980s for the films such as "Mullum Malarum" (1978), "Rosappo Ravikaikaari" (1979), "Anbulla Rajinikanth" (1984), "Nooravathu Naal" (1984), "Vaidehi Kathirunthal" (1984), "Oru Kaidhiyin Diary" (1985) and "Punnagai Mannan" (1986). In 1994, composer A. R. Rahman recorded her voice for the film "Vandicholai Chinraasu" for a duet song with S. P. Balasubrahmanyam. Later in 2014, she recorded a portion of the Thiruppugazh composed by Rahman, for the period film "Kaaviyathalaivan" and followed it with the song "Narayana" in the film "Ramanujan".