1 Bennett St. (Charles Hotel), Cambridge, (617) 861-8010.
Not noir, but a nice hotel bar with a nice crowd of Harvard Square restaurant workers after about 10:30 or 11 p.m. The most logical food are the classy sandwiches, also after 10. Before that it's too light, and the closest thing to a solid meal is a $16 steak salad. Thus this is a good place to meet friends if you're going somewhere else to eat, or if you don't want to spend the evening with them. As a drinking place, Noir could hold you for a while with friendly staff and tone.
Price range for entrées: $5 - $16.