"Since they violated party discipline, besmirched and brought disrepute to the reputation of the party, they are expelled from their respective posts and primary membership of the party," Vijayakanth said in a statement.
By immediately sacking them, party sources said, Captain, as Vijayakanth is called by his supporters, has sent a stern message that party's official line should be toed and there was no room for dissent.
The crackdown came hours after Chandrakumar led other party functionaries, including two other MLAs, in demanding Vijayakanth to go with DMK and questioned his decision to align with the People's Welfare Front (PWF).
Claiming that the decision to align with PWF was against the wishes of 95 per cent of party workers and functionaries, they also virtually gave an ultimatum to Vijayakanth to go back on his decision by noon tomorrow and align with DMK.
Under the DMDK-PWF poll pact reached last month, Vijayakanth was declared the chief ministerial candidate and his party allotted a lion's share of 124 of the 234 Assembly seats with the PWF getting 110.
Chandrakumar along with his colleague S Mohanraj - who did not side with the dissenters - had stood up for DMDK in the Assembly taking on the numerically stronger treasury benches.
C H Sekar and S R Parthiban are the other MLAs expelled. While Sekar is also the party's Tiruvallur East District Secretary, Parthiban is Salem West District secretary.
Other sacked functionaries include party deputy secretary P Murugesan, and high level panel member K R Veerappan.