If you are looking for coffee during midnight, here is one of the choice, Cafe Amazon, located in Town in Town Bangkok. It is not far from the middle of city, it is just located opposite the “The Scene” Town in Town.
There are many choices of coffee, tea, milk and cakes. You can view their menu in their official website Cafe Amazon.
GPS: 13.773907, 100.610370
It is double storey shop, you no need to worry about not enough space for you, and they provide power plugs for you to charge your devices like laptop or mobile phone. So you can bring your work to there and enjoy your coffee or tea.