1.The film was initially titled Idhu Maalai Nerathu Mayakkam and changed to Mayakkam Enna. Selvaraghavan’s wife Geethanjali later directed a movie titled Maalai Nerathu Jahannam in 2016.
2. Richa Gangopadhyay made her Tamil debut with this film. She had acted in only 2 films in her entire career – Mayakkam Enna and Osthe with STR.
3. This was Selvaraghavan’s second film with G.V Prakash after Aayirathil Oruvan.
4. This was the third film that Dhanush did with Selvaraghavan after Kadhal Kondein and Pudhupettai.
5. The film was released in Telugu as Mr Karthik.
6. Pooja Devariya and Sundar Ramu made their debuts with this film.
7. This was the first of two films in which Sundar Ramu played Dhanush’s friend. The other film was 3.
8. The film’s climax is inspired by actor Russel Crowe’s closing monologue in a beautiful mind.
9. The film’s music director was changed from GV Prakash to Yuvan Shankar Raja before GVP came on board again.
10. Richa’s voice in the film was dubbed by Deepa Venkat . Deepa Venkat and Richa both won awards in the Norway Film festival.for Best Actress and Best Voice Artist respectively.