Bucharest is 1.5 hours behind Tehran
Best overlap: 10:00 AM to 6:00 PM in Tehran is 8:30 AM to 4:30 PM in Bucharest.
For a call that suits both sides, look at 10:00 AM to 6:00 PM in Tehran / 8:30 AM to 4:30 PM in Bucharest. Because you share 8 hours of the workday, there's no need to compromise; book the time that suits the meeting, not the map. Because Bucharest and Tehran don't both observe daylight saving, plan to re-check the overlap around March and November.