Monitor Brightness/Contrast Control with Application

[durruti]

Would like to control brightness of my monitor that is DDC/CI enabled.

I know this is possible with Windows.

Is there an application that works with Yosemite?

There's "Brightness Menulet". Does it work with Yosemite and an external monitor?

 

[Caesar_091]

Take a look at these:
https://github.com/kfix/ddcctl.
https://github.com/jontaylor/DDC-CI-Tools-for-OS-X
https://github.com/superduper/BrightnessMenulet