We have been waiting for Tizen smartwatches to be compatible with non-samsung smartphones for a long time now, and there is some good news that was annouced at the Samsung Gear S2 showcase event. Samsung are allowing non-samsung devices to connect to suitable Android smartphones!!!
There are a couple of caveats, the smartphone needs to be running Android 4.4 (or above) with at least 1.5GB of RAM. The new version of the Gear manager that would allow this functionality has not been released yet, but we presume that older Tizen smartwatches would also enjoy this new found freedom.
According to Information on the Gear S2 page (dug out by Android Central), we have a list of compatible handsets (excluding Samsung's own) below: