Iwans are rectangular halls opening onto a courtyard. The Jameh Mosque's south iwan is the most elaborate, with Mongol-era stalactite mouldings, some splendid 15th-century mosaics on the side walls, and two minarets. The north iwan has a wonderful monumental porch with the Seljuk's customary Kufic inscriptions and austere brick pillars in the sanctuary.
The west iwan was originally built by the Seljuks but later decorated by the Safavids. It has mosaics that are more geometric than those of the southern hall. The courtyard is topped by a maazeneh, a small raised platform with a conical roof from where the faithful used to be called to prayer.