DynamicListener.cs

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using UnityEngine.EventSystems;

public class DynamicListener : MonoBehaviour {

    public string objectListeningTag = "Enter GameObject's tag";
    public bool thisIsListener = false;
    public bool parameter = false;
    public string sendMessage = "Enter GameObject's method name";
    public string messageParameter;

    Button b;
    GameObject objectListening;

    void Start()
    {
        b = GetComponent<Button>();
        GetObjectListening();
    }

    void GetObjectListening()
    {
        if (thisIsListener)
            objectListening = gameObject;
        else //if we are listening to another object
            objectListening = GameObject.FindGameObjectWithTag(objectListeningTag);

        if (objectListening)
            SetListener();
    }

    void SetListener()
    {
        if (b)
        {
            if (!parameter)
                b.onClick.AddListener(() => objectListening.SendMessage(sendMessage));
            else
                b.onClick.AddListener(() => objectListening.SendMessage(sendMessage, messageParameter));
        }
        else
            Debug.LogError("Dynamic Listeners belong on buttons.");
       
    }
}