DL 2646 then AA 1123 at Boston
Chicago O'Hare → Boston → Philadelphia
Timetable, Boston time
23:08DL 2646 from Chicago O'Hare at the gate
20:50AA 1123 to Philadelphia leaves the gate
21 h 42 apart on the timetable, overnight
AA 1123 leaves 21 h 42 after DL 2646 arrives on the timetable: more than half a day, so not a connection we count.