Ireland eased to the European Championships for the first time since 1988 by beating Estonia 5-1 on aggregate, after a 1-1 draw in Dublin.
Ireland full-back Stephen Ward increased his side's 4-0 aggregate lead in the play-off tie with a close-range 31st-minute finish.
But Estonia skipper Konstantin Vassiljev denied the Republic of Ireland victory on the night. The midfielder blasted home a 30-yard drive which eluded Shay Given to hand the visitors a 57th-minute equaliser at the Aviva Stadium.
Cristiano Ronaldo and Helder Postiga both scored twice as Portugal reached the finals with a 6-2 win over Bosnia but the scoreline did little justice to the drama at Lisbon's Stadium Of Light.
The visitors, who had held on for a gallant goalless draw in the first leg in Bosnia, twice narrowed the deficit to a single goal despite being hampered by the 54th minute sending-off of Senad Lucic.
A thunderous eighth minute free-kick from Ronaldo and an even more powerful long-range drive from Nani on 24 minutes appeared to have settled home nerves and sent the favourites through.
But Zvjezdan Misimovic ensured the outcome of the game still hung by a thread at half-time after he converted a 41st minute penalty awarded after Fabio Coentrao was ruled to have handled in the box.
Portugal regained the initiative through Ronaldo on 53 and when Lulic was shown a straight red immediately afterwards for arguing with the referee, it appeared the Bosnian challenge was finally over. But the visitors reduced the deficit again on 65 through Emir Spahic before the 10 men tired, with two late Postiga strikes and a free-kick from Miguel Veloso giving a lopsided look to the scoreline.
Croatia also cruised into next year's finals after playing out a 0-0 draw against Turkey in Zagreb four days after their decisive 3-0 first-leg win in Istanbul.
Ivica Olic, Mario Mandzukic and Vedran Corluka had all scored to make tonight's game a virtual formality, although Croatia boss Slaven Bilic insisted his side's job remained only half done.
Despite a brave Turkish bid for an away win the Croatians held firm and qualification for their third consecutive continental finals - and revenge for their Euro 2008 quarter-final loss to the Turks - was secured.
Czech Republic ensured their place after a narrow 1-0 win proved to be enough against Montenegro.
Petr Jiracek scored the only goal of the game in the 81st minute to give them a 3-0 win on aggregate.
The Czechs won the first leg 2-0 in Prague on Friday with goals from Vaclav Pilar and Tomas Sivok which meant the slender win sealed their progression to Euro 2012.