If you search for "best time to drink coffee" on Google, you'll be overwhelmed by the links. But only a few linked articles have scientific backing.
A 2010 Brazilian and French researchers' article suggests the meal time for coffee in order to take advantage of the beneficial effect of coffee on insulin, to lower the risk of diabetes. (Incidentally, some unsubstantiated articles link coffee with an increased risk of diabetes!) I did not find any article making a distinction between before-meal and after-meal for coffee. It probably doesn't matter much except on subjective grounds. I personally wouldn't drink too much, too concentrated coffee on an empty stomach, or I would feel nausea.
A group of Oxford researchers suggest 11 AM as the best time for coffee, because that's the time people will take the greatest pleasure in drinking it, according to their mathematical formula.
The rest of the articles are generally opinions, or personal preferences, which nevertheless may be amusing to read.