Kanimozhi, DMK chief Karunanidhi's daughter, CPI national Secretary D Raja and former MP Tiruchi N Siva of the DMK filed their nomination papers on Friday for the June 15 Rajya Sabha polls from Tamil Nadu.
Union Surface Transport Minister T R Baalu, Tamil Nadu ministers and senior CPI leader R Nallakannu were present when they filed their papers.
V Maitheriyan and Ilavarasan of the AIADMK had already filed their papers.
The Congress, which could get one of its nominees elected to the Upper House of Parliament, was yet to name its nominee.
Given the coalition strength in the Tamil Nadu Assembly, the DMK and its allies can win four out of the six seats for which polling will be held on June 15.
DMK will be contesting two seats while it has left one seat each to allies Congress and CPI.