I just did a paper on the Coptic Church and there is a series of volumes published by the American University in Cairo that are good resources for history of the Copts.
The Early Coptic Papacy: The Egyptian Church and Its Leadership in Late Antiquity
I only read the first one I linked since I was focused on the period prior to the Arab Conquest of Egypt, but it did a fantastic job. Starts with Saint Mark and goes to the period I just mentioned, ~650 A.D.