The calculated distance (air line) between Zürich (Kreis 2) / Wollishofen and Riehen is approximately 44 miles respectively 72 kilometers.
By car or train, the actual journey to Riehen is certainly longer, as only the direct route (as the crow flies) between Zürich (Kreis 2) / Wollishofen and Riehen has been calculated here.
Air line (approximately)
72 kilometers
39 nautical miles