The unidentified brothers, who are Kurdish refugees, were involved with a group set up by a Norway-based Islamist cleric, Najmaddin Faraj Ahmad, also known as Mullah Krekar.
Prosecutors said in a statement that Krekar's group—which also wasn't identified—was part of the al-Qaida network and dedicated to establishing worldwide Islamic rule.
"The newly-founded terrorist organization is alleged to pursue a multileveled strategy to attract new members and supporters, and by this means to strengthen the existing organizations of the al-Qaida network," the statement said.
The group used various websites to attract Islamists and, after their commitment to the jihadist cause had been vetted, grant them access to secret online chat rooms where terrorists and their sympathizers could communicate, Swiss prosecutors said.
The older brother is accused of setting up and financing the websites, which were also used to publish videos from al-Qaida leader Ayman al Zawahiri and his predecessor Osama bin Laden.
The younger brother is accused of actively participating in the chat rooms which his brother operated "in full knowledge of its terrorist goals," according to Swiss prosecutors.
If convicted, the men could face prison terms of up to five years. Both are currently free on bail.
Krekar received a one-year prison sentence in August for making death threats against Norwegian politicians, influencing witnesses and inciting terror. The sentence came in addition to a five-year term he got in March for making death threats against Norwegian officials.