using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    class A

    {

        public int Index { get; set; }

        public bool State { get; set; }

    }

    public static void Main()

    {

        List<A> list1 = new List<A>() {

            new A(){ Index = 1, State = false },

            new A(){ Index = 2, State = false },

            new A(){ Index = 3, State = true },

            new A(){ Index = 4, State = false },

            new A(){ Index = 5, State = false },

        };

        List<A> list2 = new List<A>() {

            new A(){ Index = 1, State = false },

            new A(){ Index = 2, State = true },

            new A(){ Index = 3, State = false },

            new A(){ Index = 4, State = false },

            new A(){ Index = 5, State = false },

            new A(){ Index = 6, State = true },

            new A(){ Index = 7, State = false },

        };

        Dictionary<int, A> dict = list1.ToDictionary(x => x.Index, y => y);

        foreach (var item in list2)

        {

            if (dict.ContainsKey(item.Index)) {

                dict[item.Index].State &= item.State;

            } else {

                dict.Add(item.Index, item);

            }

        }

        foreach (int key in dict.Keys)

        {

            Console.WriteLine("{0} {1}", key, dict[key].State);

        }

​

    }

}