The Osmanağa Mosque, located in Kadıköy, was commissioned by Osmanağa in 1612 during the reign of Sultan Ahmet I. The mosque was built where a mescit –which had gradually fallen into disrepair –once stood.
Built on a rectangular plan, the mosque was constructed of stone and brick. The mosque is supported by wooden columns and on its left and right faces are forty windows. With one, one-tiered minaret, the mosque also has an historical sycamore tree in its courtyard which is said to have been planted on March 14th, 1879.