In 2011, his third directorial "Ko", starring Jiiva, Ajmal Ameer, Piaa Bajpai and Karthika Nair released to very positive response from media and public. One of the critics neatly summarized it by saying "For an audience numbed by predictable Kollywood potboilers week after week, here is an original offering from KV Anand, a fearless filmmaker who doesn't insult your intelligence. He is able to cater to the needs of both the elite as well as mass audiences, which should be applauded." Anand's fourth directorial venture saw his collaborate with Suriya again in "Maattrraan" (2012), and was inspired to make the film after watching a documentary about the conjoined twins Chang and Eng Bunker. While preparing the script, he worked closely with a team of doctors to ensure the medical condition of open-heart transplant, as shown in the film, could be showcased as realistic as possible. However, the movie opened to mixed reviews from the critics and became a success at the box office.