Robin Harper was the first MSP for the Scottish Greens from 1999-2011. His leaving will make no difference to the Harvie-Slater-Chapman travesty that is the Scottish Green party now though.
https://www.thetimes.co.uk/article/bcd9e612-3159-11ee-b862-55515d26d392?shareToken=5fb55429934ec06bbdbbf57a1267757e