There is probably a very simple solution for this but I can\'t get it working.
I have got multiple classes in my Cocoa file. In one of the classes class1
You could expose the variable in class2 as a property. If class1 has a reference to class2, class1 can then see the variable. Honestly, though, it sounds like you're a beginner to both Objective-C and object oriented programming. I recommend you read up more on both.
Here is a place to start for object oriented programming with Objective-C.