Based on the Cooper SE, Mini has developed an all-electric convertible car: Mini Cooper SE Cabriolet. This is a one-off prototype explicitly developed for illustrative reasons. This is the first time it has been shown to the public, and it's happening at "MINI takes the States" in the United States.
Mini only made one Cooper SE electric convertible car prototype to show off its ideas. The Mini brand has not said if it intends to mass-build a convertible version of its electrified vehicle.