The Democratic Unity Coalition is an electoral and political coalition between the Portuguese Communist Party

Portuguese Communist Party

The Portuguese Communist Party is a major left-wing political party in Portugal. It is a Marxist-Leninist party, and its organization is based upon democratic centralism. The party also considers itself to be patriotic and internationalist....

  and the Ecologist Party "The Greens" (Portuguese

Portuguese language

Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

: Partido Ecologista "Os Verdes" or PEV). The coalition also integrates the political movement Democratic Intervention

Democratic Intervention (Portugal)

The Democratic Intervention is a Portuguese left-wing political association founded in order to promote and defend socialist ideas in Portugal. Members of it take part as independents in the electoral alliance Unitarian Democratic Coalition, along with the Portuguese Communist Party and the...

 .

The coalition was formed for the first time in 1987 in order to run to the simultaneous legislative election

Portuguese legislative election, 1987

The Portuguese legislative election of 1987 took place on July 19. In the last election, in 1985, the Social Democratic Party had achieved a relative majority, thing that made its government very weak, managing to survive in coalition with the Democratic Social Center and the Democratic Renovator...

 and European Parliament election

European Parliament election, 1987 (Portugal)

The European Parliament election of 1987 in Portugal took place on 19 July 1987. It was the election of all 24 MEPs representing the Portugal constituency for the remainder of the 1984-1989 term of the European Parliament...

 that were held on July 19 of that year.

Since the beginning of the coalition, the member parties have never participated separately in any election.