Formed in 1980 as a loose coalition of pacifists, socialists environmentalists and feminists, the Greens may become kingmakers after Germany's September 2013 federal election.
Here is a look at significant Greens moments in Germany:
October 1992 - Germany's Greens co-founder Petra Kelly is found dead. Kelly was one of its first members of parliament. She was shot dead by her partner, former general and Green politician Gert Bastian, who then killed himself.
Sept/Oct 1998 - Social Democrats under Gerhard Schroeder win the federal election. Schroeder seals a coalition with the Greens and names Greens leader, Joschka Fischer, as foreign minister and deputy chancellor. The Greens join the federal government for first time.
May 1999 - The Greens emerge strengthened from a turbulent party congress where pacifists' anti-NATO demands are defeated. Party leaders and analysts say the Greens had come of age by beating back left-wing demands for an immediate halt to NATO's Yugoslav bombing campaign.
November 2001 - The Greens vote by a large majority to back the deployment of troops in Afghanistan, averting the collapse of the coalition government. Parliament approves the motion the next month.
September 2002 - Fischer confirms his status as Germany's most popular politician as he leads his Greens to their best election result.
March 2003 - Fischer, addressing the U.N. Security Council, says it is still possible to disarm Iraq peacefully and that Berlin therefore rejects war on Baghdad.
November 2005 - Angela Merkel's new coalition government of conservatives and Social Democrats (SPD) takes office after defeating Schroeder's SPD-Greens alliance in elections.
June/July 2011 - Lawmakers in the lower house of parliament - with opposition members from the Greens and SPD joining Merkel's center-right coalition - approve an end to nuclear energy by 2022 following Japan's Fukushima disaster. The upper house votes for it a week later.
March 2012 - Following elections in the German state of Baden-Wuerttemberg, the Green Party heads its first-ever state government, ending 58 years of rule by the conservative CDU. Later in the year Greens candidate Fritz Kuhn becomes mayor of Stuttgart, the first German state capital to elect a Green mayor.
January 2013 - The Social Democrats (SPD) and Greens edge Merkel's conservatives from power in Lower Saxony by one seat, reviving its hopes of defeating her in the September 2013 election.
(Reporting by David Cutler, London Editorial Reference Unit)