However, disagreements had prevailed over the selection of Kilicdaroglu, with one of the biggest parties in the opposition alliance refusing to endorse his nomination.
Kilicdaroglu heads the center-left Cumhuriyet Halk Partisi (CHP) party.
Why is there a rift among the opposition?
The nationalist IYI party, the second-strongest force in the alliance, on Monday proposed two other CHP members — the mayor of Istanbul, Ekrem Imamoglu, and the mayor of Ankara, Mansur Yavas as candidates for vice president.
The CHP accepted the compromise in an attempt to reunite the opposition bloc.
IYI leader Meral Aksener had already said on Friday she would not back Kilicdaroglu's nomination and walked away from the six-party group.
She had hoped Imamoglu or Yavas would be the main candidate. The two mayors both performed better than their party leader in public opinion polls.
"I'm sorry to say that, as of yesterday, the Table of Six has lost its ability to reflect the will of the nation in its decisions," Aksener told reporters after meeting senior IYI party officials.
According to Aksener, the chances of Kilicdaroglu winning are slim.
What does the opposition want?
The bloc vowed in January to end the presidential system set by the country's leader, Erdogan, and bring back parliamentary rule.
Erdogan has been in power for the past 20 years.
He gained additional powers after winning the 2018 elections and abolishing the position of prime minister.
According to the opposition's mandate, the president would become more of a ceremonial head. The incumbent would not belong to a political party, be stripped of presidential powers to issue decrees, and will hold a maximum of seven-year term.
The alliance also announced that they would aim to fight inflation and within two years, will reduce it to a single-digit percentage.
Also, it aims to continue Turkey's bid for membership of the European Union and restore independence to the country's central bank.
Who is Kemal Kilicdaroglu?
The 74-year-old Kilicdaroglu is the long-time leader of the main opposition party of Turkey — the CHP.
His nomination for the presidential election was backed by his own party and four other smaller parties in the alliance.
He also has the support of the country's mayors.
In the past 13 years of leading the CHP, Kilicdaroglu has not managed to win a national election.
aa/ar, rt (dpa, AP)