What is the difference between clonazepam and clonopin?

They are the same: Clonazepam is the generic (chemical)name for Klonopin (which is the original branded name). Since Klonopin went generic, there are now many manufacturers who produce the generic version. While all of those preparations contain clonazepam, some may be more effective than others given different binders, dyes and other inert constituents of the various companies' products.