If you want one evening out of the old city, make it Karakoy. The waterfront between Galata Bridge and Tophane holds most of the city’s good bars within a few hundred metres, and almost all of them look out over the water.
Rooftops are the draw. Several buildings along Kemankes Caddesi have terraces facing the Bosphorus with the old city lit on the far shore — the view that makes people book a second night. At street level there are meyhanes, coffee bars and small restaurants.
Reserve a rooftop table at weekends. From Romance Istanbul Hotel it is a twenty-minute walk over Galata Bridge, and the same walk back after dark is part of the evening.