A court in Dusseldorf sentenced the men to jail terms from three years and eight months to nine and a half years.
It is believed the five men were in the same social circle as the Tajik-born perpetrator behind the Stockholm lorry attack of April 2017, and the Macedonian-Austrian national who shot down four people in Vienna in November 2020.
Sunatullokh K, 26, was handed the longest sentence for planning to shoot dead a YouTuber based in Neuss, western Germany, who was critical of Islam.
The assault was foiled by investigators, the court heard.
Farhodshoh K, 33, received eight and a half years for plotting a contract murder in Albania.
The court said the killing was not carried out only because the perpetrators had "doubts about the identity of the target" during surveillance.
The other three men — Muhammadali G, 34; Azizjon B, 29; and Komron B, 25 — were convicted for taking part in a terrorist organisation.
"Driven by their radical Islam conviction," they had sought to carry out attacks for ISIS, said the court.
All five had arrived in Germany as refugees.
From 2019, the men were in contact with a leading ISIS member in Afghanistan who provided them with radical ideology.
ISIS-linked militants have committed several violent attacks in Germany in recent years, with the worst being a ramming attack at a Berlin Christmas market in December 2016, which killed 12.
Meanwhile Norway’s domestic security agency said Wednesday that a man has been arrested in Oslo on suspicion of taking part in a terror organisation, and that another person identified as a Norwegian student has been arrested in Bulgaria in a coordinated action.
The suspect placed in custody in the Norwegian capital will face a pre-trial custody hearing later Wednesday following his arrest a day earlier. He hasn't been identified
Trond Hugubakken, a spokesman for the agency, known by its acronym PST, told Norwegian broadcaster NRK that the arrest in Bulgaria took place on the strength of a European arrest warrant issued by the prosecuting authority in Norway and added that there had been an investigation in the Scandinavian country