Eldest Son) is a 2006 Indian Tamil-language action film directed by R. Sarathkumar, starring himself alongside Nayanthara, Vadivelu and Vijayakumar.

Dheeran runs into the evil axis of politico and police web as represented by the corrupt Minister Shanmuga Vadivelu and a venal cop Alankaram.

The film was launched on 15 September 2005 with R. D. Balaji, an advertisement filmmaker making his feature directorial debut and Cheran writing the screenplay.

The climax was shot at sugar mill in Porur during the first schedule which "was the most difficult part to shoot" as it involved "close to 850 artistes" and was completed within eight days.

[11] The film was released on 21 October 2006, during Diwali, and opened alongside Varalaru, Vattaram, Vallavan and Dharmapuri.

[12] Indiaglitz wrote, "Sarath the director has worked hard in giving voice to a burning issue.

[13] Venkatachari Jagannathan of Rediff.com rated the film two stars out of five, saying, "On the whole, Thalaimagan is like reading a morning paper in the evening".

It is one man taking on a corrupt system controlled by a powerful politician and his associate, a she-devil of a cop!".

[16] Cinesouth wrote "The basic story line is strong but the plan of the screenplay is haphazard.