using Newtonsoft.Json;

using System;

​

// https://stackoverflow.com/a/44454181/4295017

​

public class Program

{

    public static void Main()

    {

        var obj = new Organization { Address = new Address() };

        var json = JsonConvert.SerializeObject(obj, Formatting.Indented);

        Console.WriteLine(json);

    }

}

​

public class Thing

{

    [JsonProperty("@context")]

    public string Context { get { return "http://schema.org"; } }

    public bool ShouldSerializeContext() { return this is Organization; }

}

​

public class Organization : Thing

{

    [JsonProperty("address")]

    public Address Address { get; set; }

}

​

public class Address : Thing

{

}

​