using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        IEnumerable<(int, char)> list = new List<(int, char)>

        {

            (1, 'A'),

            (2, 'B'),

        };

​

        List<int> intList = new List<int>();

        List<char> charList = new List<char>();

        foreach (var item in list)

        {

            intList.Add(item.Item1);

            charList.Add(item.Item2);

        }

        Tuple<IEnumerable<int>, IEnumerable<char>> result = Tuple.Create(intList.AsEnumerable(), charList.AsEnumerable());

        Console.WriteLine(JsonConvert.SerializeObject(result));

    }

}