Following a heavy election defeats, the joint leaders of the German Greens, Omid Nouripour and Ricarda Lang said they would step down for a new leadership to be elected at the party congress.
The decision comes following series of heavy election defeats for the party, which serves in Social Democrat Chancellor Olaf Scholz's coalition.
The move, buffeted by voter worries over the scale of the economic challenges facing Germany and by fierce debates over migration.
Nouripour in a news conference said, "The result in Brandenburg on Sunday is a sign our party is in its deepest crisis for a decade. It is time to lay our beloved party's fate in others' hands."
According to Nouripoir, a new leadership will be elected at the party's upcoming congress in mid-November to champion the course of the party.
The Greens failed to clear the 5% hurdle needed to enter parliament in Brandenburg on Sunday and in Thuringia earlier in September.
Along with their SPD and Free Democrat coalition partners, they also suffered big losses in their vote share in elections in Saxony and for the European Parliament this year.
Also speaking, Lang said, "The party needs to prepare for a dramatically changed political climate."
A new left-wing populist party and the far-right Alternative for Germany (AfD) have outperformed all three coalition parties this year, while the main opposition conservatives are leading in national polls.
"Next year's election is not just any election," Lang said, referring to a scheduled national vote. "(It will be a choice between) a country focussed on achieving prosperity by sticking to climate neutrality or a country run by people who want to back away from all that."
The position of Robert Habeck, a senior Greens party member who is Scholz's deputy and Germany's economy minister, is not directly affected by the co-leaders' decision.
The parliamentary leader of Scholz's centre-left SPD, Katja Mast, said she believed the Greens would want to stay in the governing coalition.
"I assume this is a re-organisation within the Green Party and not within the government and the Greens benches in parliament," she said.