On Saturday, Naidu met Samajwadi Party President Akhilesh Yadav and Bahujan Samaj Party President Mayawati.
He held talks with Akhilesh Yadav for about 70 minutes at the Samajwadi Party office yesterday.
Akhilesh Yadav later tweeted: "It is a pleasure to welcome Hon'ble chief minister Shri Chandrababu Naidu ji to Lucknow."
Later Naidu went to Mayawati's Mall Avenue residence. Senior BSP leader Satish Chandra Misra was also present there. Mayawati greeted him with a bouquet while he gifted her box of mangoes. He had also gifted mangoes to Akhilesh Yadav. His meeting with Mayawati also continued for over an hour.
In his meetings held separately with the two leaders, the Andhra Pradesh Chief Minister is believed to have impressed upon the two leaders the need to keep the BJP out of power, if it did not get a majority on its own.
Sources said that he convinced both the leaders that their stature and respect would not be compromised in the proposed front.
Naidu had arrived in Lucknow after meeting Congress President Rahul Gandhi in Delhi earlier on Saturday.
He had met CPI-M leader Sitaram Yechury and Aam Admi Party chief Arvind Kejriwal on Friday and had discussed with them the possibility of a tie-up in the post-result scenario.
Naidu's efforts come ahead of UPA Chairperson Sonia Gandhi's proposed meeting of opposition leaders on May 23, the invitations for which have already been sent out.
Naidu's TDP was a part of the NDA, but quit the alliance a few months ago. The Congress and other opposition parties have exuded confidence of forming the next government.
Earlier during the day, he wrote to the Election Commission, claiming that "continuous" telecast of Prime Minister Narendra Modi's "private activities" at Badrinath and Kedarnath shrines is violation of the poll code and should be stopped
(With inputs from Agencies)