Henry Millar, 36, from Kilmarnock, was killed when his white Kia Cee'd hit a tree after mounting a kerb near the Grassyards Interchange at about 18:50 on Sunday.
At 23:20 the same night a 31-year-old man died after his car hit a tree on the A77 near Monkton in South Ayrshire.
That crash, involving a grey Ford Kuga, happened at the Dutch House roundabout.
Police said the car was reported to be travelling northbound when it mounted the roundabout.
The driver was taken to Crosshouse Hospital where he was later pronounced dead.
Police have appealed for anyone with information about either accident to contact them.
Two men have died in separate crashes on the A77 in Ayrshire after their cars left the road and hit trees.