I have purchased a license for EndNote X5 for the Windows version that runs on myx desktop PC. However, I need an additional Mac version for my mobile PC. According to the FAQ list on the EndNote home page ‘The individual End User License Agreement allows a single license holder to install EndNote on up to three of his/her computers.’ Is it possible to obtain the software and activation keys for both operating systems without having to purchase a second license?
I recommend you contact the Sales team with this question - http://endnote.com/encontact.asp.
- Mathilda, the EndNote team
… nice idea 
I wrote to Sales Information already twice, but so far they did not deem me worthy of a reply … 
That is when I pick up the phone!