This is something I needed for a larger project. It is a very low poly version of the Empire State Building.
Adjust the invert node and the emission node to change from night to day texture on the building.
For the preview image, I also changed the sky texture from day to night.
This blend does not have very many details on it as it is only meant to be seen in silhouette for my project, but you may find it useful.
Hope you like it.
I have just added an image of the finished project wherein I used the building as part of it. I think it came out pretty well!