Cassis will meet Iranian President Hassan Rouhani, Foreign Minister Mohammad Javad Zarif and Secretary of the Supreme National Security Council Ali Shamkhani during the September 5-7 trip, Swissinfo.ch reported.
He shared on Twitter that he had also spoken to US Secretary of State Mike Pompeo about the planned visit.
On the agenda are discussions about the humanitarian aid channel for Swiss-based companies to send medicines and other essential goods to Iran, the report said.
Discussions will also focus on bilateral relations and Switzerland’s protecting power mandates.
Switzerland has represented US interests in Iran since 1980.