DMK working president MK Stalin, who is set to be elected the party president, filed his nomination for the post at Anna Arivalayam, the party headquarters, in Chennai in Tamil Nadu today.
Senior leader and party principal secretary Duraimurugan filed the nomination for the post of treasurer, hitherto held by Stalin.
They are likely to be elected during the party's General Council meeting on August 28 in Chennai.
The process to elect Stalin as DMK chief following the death of his father and party chief M Karunanidhi began with the 65-year-old leader formally filing his nomination for the post.
Before filing the papers, Mr Stalin, Mr Duraimurugan and senior party colleagues T R Baalu and A Raja visited Dayalu Ammal, Karunanidhi's wife, at her Gopalapuram residence.
Later they also met party veteran and general secretary K Anbhazhagan and headed straight to the memorials of DMK founder and former Chief Minister C N Annadurai and Karunanidhi at the Marina beach-front and paid floral tributes, party sources said.
MK Stalin, who was given a rousing reception on his arrival by partymen at the party headquarters formally, submitted the nomination papers to DMK Organising Secretary R S Bharathi.
Also the names of MK Stalin and Mr Duraimurugan were proposed by all 65 DMK district secretaries for the post of president and treasurer respectively.
Talking to reporters, A Raja said MK Stalin and Mr Duraimurugan would be elected "unanimously" at the General Council meet.
Sibling rivalry between Mr Stalin and his elder brother MK Alagiri came to the fore recently, when the latter claimed that true loyalists of Karunanidhi were with him.
MK Alagiri, who was expelled from the party by Karunanidhi in 2014, has been questioning the leadership of Stalin. He has announced he would lead a peace rally in Chennai on September 5, to the mausoleum of Karunanidhi.
MK Stalin, the younger son of Karunanidhi, had held several party posts, including that of treasurer and youth-wing secretary.
His journey in the party began early when he campaigned in the 1967 elections as a 14-year-old school student. He became the party's youth-wing secretary in 1984.
He was put in prison under Maintenance of Internal Security Act in 1976 during Emergency.
Mr Stalin's growth has been steady and he became party deputy general secretary in 2003. He was re-elected treasurer for the second five-year term in January 2015.
He became an MLA for the first time in 1989 from Thousand Lights constituency in the city from where he was re-elected thrice.
In 2006, he became the Municipal Administration Minister in the DMK government and went on to become the Deputy Chief Minister in 2009.