The Mosque of Uthman El-Katkhuda or the Mosque of Kikhya situates in the corner in which El-Gumhuriya Street and Qasr El-Nil Street intersect. It is the only remaining part of the complex that was established by Uthman Katkhuda in the quarter of El-Azbakiya.
The area of El-Azbakiya was constructed in the Ottoman period by Azbak Ibn Tutukh. Emir Azbak was the Atabek or Supreme Commander of Sultan Qaytbay and he played a great role in organizing campaigns against the Ottoman in the 15th century. Emir Azbak complex was consisting of a palace, a public fountain, and a commercial center that was destructed as an impact of the works of construction of Uthman Katkhuda Complex in an adjacent area.
Uthman Katkhuda complex was once including a mosque, a fountain, a public Hammam and a commercial center also. Yet only the mosque remained while the rest of the monument disappeared. the process of restoration of the mosque took about 11 years and finally it was opened again in 2000. Although most of the decoration of the interior part of the building is in a ruinous state, the mosque is still used as a place for prayer.
You can get more information here.