"We will contest Bihar assembly polls with SJD-D led by former Union Minister Devendra Prasad Yadav, the NCP and the NPP headed by former Lok Sabha Speaker P A Sangma as third front alternative in Bihar," SP National General Secretary Ram Gopal Yadav said at a joint press conference with leaders of these parties.
"The coordination committee of third front will meet in Patna tomorrow to decide candidates for the first phase of the Bihar polls for which filing of nominations have already started," Devendra Yadav said.
49 assembly seats will go to polls in the first phase on October 12 and the last date for filing of nominations for first phase is September 23.
Former Rastriya Janata Dal leader Raghunath Jha, who formally joining SP at the venue of the press meet, said he left Lalu Prasad's party as he was not getting "due respect" there.
"I thank Mulayam Singh Yadav for accepting me in his party fold," he said.
Asked about the front's chief ministerial candidate, Ram Gopal Yadav said it has not been decided so far.
About parting ways with the alliance of Lalu and Nitish Kumar (Janata Dal-United), Ram Gopal said that it was not possible for SP to merge with it and give up its identity.
"I know it was a conspiracy. Had we joined them we would have not only lost the symbol but also the party," he said.
On allegation of rival parties that he was helping the BJP in Bihar by splitting of opposition votes, Ram Gopal said, "Let them make allegations. In politics, such charges are made."
Besides Jha, JD-U MLC Munna Singh joined SP.
Assembly polls in Bihar will be fought in five phases between October 12 and November 5 in a high-stakes battle, seen as a major popularity test for NDA spearheaded by Prime Minister Narendra Modi, and incumbent Chief Minister Nitish Kumar, who is in alliance with RJD and Congress.
Polls to the 243-seat Assembly would be held on October 12, 16, 28, November 1 and 5. Counting to votes will take place on November 8.