Hi there!
I’m not familiar with that particular plugin, but our plugins generally play well with most plugins that are coded according to WordPress best practices.
Is there something in particular that you are looking to do with Constant Contact and our plugins together?
I would recommend installing The Events Calendar (free) on a testing site along with Constant Contact to try it out. If you’re interested in any of our premium add-ons, we do offer full refunds within 30 days of purchase, so feel free to try them out as well! Please let me know if you have any other questions.
Thanks,
Jennifer