How do I add bookmark on Android (Firefox or Chrome) so it appears on PC
At least my version of Chrome (32.0.1700.107) on OS X has a menu called Mobile Bookmarks under Bookmarks, where I can see my phone's bookmarks. And I can add bookmarks to my desktop Chrome from Android from Menu -> Favorite (the star) -> Folder -> Desktop bookmarks.

Try using Chrome Beta for Android if yours doesn't have that feature.