Thunderbolt display problem

I have thunderbolt display that goes along with my iMac. Most of the time I don't use this display unless I'm working from home and I need to keep many terminal windows open. But when I don't need this display it looks like I can not turn it off. This means this display is turned on when ever I'm using iMac. I searched online and haven't found a native solution. There is an app SwitchResX that would do this, it seems. But it just doesn't make sense to not to be able to do it. So far, what I have been doing to solve this problem is to plug the thunderbolt cable off the iMac and this would turn the display off. But it's frustrating to do this when you need to do this many times as you need to reach for the cable at the back of the iMac. So, I looked at the SwitchResX and it looks like a great tool if you really need all the functionality it provides. This is not the case for me and so what I'm doing these days is to simply make the display brightness to zero. Just to let you know, when you press brightness key on your keyboard it acts only on your iMac display. In order to reduce or increase the thunderbolt display brightness just press brightness key while holding control key. This would do the trick. In any case, I'd be great if someone could post any other solution that's working out well.