Never lose your important iPhone contacts
iPhone is not just a cell phone, it means more to you. You have added so many contacts on it and don't want to lose any of them, why not backup the contacts to Mac as a readable file or sync the contacts to Mac Address book. Get a tool like iMacsoft iPhone Contacts to Mac Transfer to help you, export all contacts or selected contact to Mac hard drive.
Do what iTunes can't
Though iTunes can't sync iPhone and allows you to the whole data on iPhone to Mac, it doesn't export a single contacts to Mac, once get the iPhone contacts to Mac backup software, it is easy to get the contacts out of iPhone and put it on Mac, thus you can add to contacts to other mobible phone or other iPhone.