There are dozens of mind mapping solutions out for the Mac. I'm a little baffled that nobody has left some praise for iThoughsX, so I guess I'll have to jump in.

Great app, super feature set, very responsive developer. And now, just over a year later, the app has flown through v1 and v2 to reach v3. That might have been how v1.0 entered the world, but it was not what I found in v.1.11, for it was far more capable and stable than I'd dared to hope. My expectations were low: I was hoping for a stable viewer of my iPad mind maps with basic editing capability. 1.11 on 1/6/15, to support and encourage the developer. So great was my delight when at length I discover a Mac version had come on the scene, simply because it promised to increase the utility of my iPad version manyfold. Its utility was harshly limited, though, in that there was no corresponding Mac application. I first met iThoughts as an iPad app where it shined brightly amongst the competition, and it helped me focus my thoughts on many occasions. It's fast, easy to use, feature-rich, but those features remain out of my way unless I need them I need. This is an outstanding mind-mapping application.

Mac os x mind mapping software