Im new D: Collisions 2D Destroy help

So, I'm starting with unity 5 and i want to destroy an enemy by using a collision in 2D. If the enemy hits the player the player gets destroyed, but if the enemy touches an empty object with rigidbody(its kinematic and gravity 0) and a box collider, the enemy does not destroys.

This is the code where I destroy the enemy(or at least that's what I hoped for):

using UnityEngine;
using System.Collections;

public class DestroyEnemyCars : MonoBehaviour {

void OnCollisionEnter2D (Collision2D col)
{
if (col.gameObject.tag == "Enemy Car")
{
Destroy (col.gameObject);
Debug.Log ("Something or whaaaaaaaat"); //The console never shows this message :s
}
}
}

and here i destroy the player:

void OnCollisionEnter2D(Collision2D col)//llamado cada vez que este gameobject sienta una collision con otro objeto 2D
{
if (col.gameObject.tag == "Enemy Car") //se compara con el tag que se hizo
{
Destroy (gameObject);
}
}
I really don't know what I'm doing wrong, hope for some help.