The opening match of the 80-game group stage sees Heart of Midlothian take on Dundee United at Tynecastle on Friday night, live on BT Sport at 7.45pm.
There are eight groups, with matches to be played over five matchdays between this weekend and the end of July.
The eight group winners and four best runners-up progress to the last 16, where they will be joined by European entrants Celtic, Rangers, Kilmarnock and Aberdeen.
The draw for the last 16 will be made on Sunday July 28, with ties to be played on the weekend of August 17/18.
