Very long story as to why this happened, but a neighbor stole 2 pounds of Puron from my A/C one night. Because it was dark he didn't realize it was a Puron system. He has since put this in Freon systems. Has he damaged those systems?

They are both freon, just different types and carrier. Yes, he will most likely damage his system due to inherent incompatibility. His problem in more ways than 1.

Follow up information: My system was Carrier Puron R410a. The neighbor works as a handyman for apt complexes and often repairs air conditioners. He works almost exclusively with Freon R22. Long story as to why he stole this from my A/C but he did it at night and didn't realize it was R410a, and has since put it in R22 systsems. I'm reading that it will damage those systems.

Okay, first off, "freon" and "puron" are brand names of REFRIGERANTS. So, puron r22 would be just fine with freon r22, they are both r22 refrigerants, just different manufacterers. However, r410a is definitely not compatible with r22, so yes, the system he added the 410 to will not work correctly and has most likely already ruined the complete system. That's what you get for being a thief, and a stupid one at that. I suggest turning him into the authorities. Not only the local police, but also to OSHA. I suspect he is not licensed to deal with refrigerants, and that holds a mighty hefty penalty. These type of people give the rest of us real pros a bad name and Im sick of it.