I am going to introduce you Red Sky Bar located on the 55th floor of Bangkok Centara Grand At Central World ~♡
It has a nice atmosphere that just suits for a glass of cocktail. And you can enjoy the night view of Bangkok while up-tempo music playing on the background.
The opening hours is from 4p.m. to 1a.m. and the happy hours starts from 4p.m. to 6p.m.
If you want to relax while enjoying the night view of Bangkok, I recommend you to visit here after the happy hours^^