Azmi, also a human rights activist, was assassinated in 2010 in Mumbai. The 2013 biopic was based on the lawyer, who died at the age of 32.
Mehta and Rao took to Twitter to remember Azmi.
"Remembering Shahid Azmi. Thank you," tweeted Mehta.
Rao wrote, "Remembering our Hero Shahid on his death anniversary. You will always be in our thoughts. Thank you @mehtahansal sir for sharing his story."
The movie earned Rao his maiden the National Film Award for best actor and Mehta bagged the best director honour at the ceremony.