List list = [ ('a', (1,2)), ('b', (2,3)), ('c', (3,4)) ] // Dart >= 2.3: var result = { for (var v in list) v[0]: v[1] }; // Dart < 2.3 var result = Map.fromIterable(list, key: (v) => v[0], value: (v) => v[1]);