This will take a bunch of PDFs (up to 15), email it to your Kindle, and convert it to .mobi format so that you can easily read. Make a folder in Dropbox pdfs_to_kindle. Drag files to that folder and it will automatically email to your Kindle and convert it on the way.

This Trigger fires every time any file is saved in the folder you specify. NOTE: will process up to 15 files per polling period.

This Action will send an email to up to twenty recipients from your Gmail account.

PDF-->Dropbox-->Kindle /Mobi