2D destroy on collision not working

I want anything that enters that hitbox to be destroyed, however nothing actually happens, I am quite sure there is something wrong with my script, don’t know what though, i have pretty much done as unity tutorials have told me.

this is my script:

using UnityEngine;
using System.Collections;

public class Deleter : MonoBehaviour {

	

	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void OnCollisionEnter2D (Collision2D col) {
			
		

			DestroyImmediate(col.gameObject);
			
		print (col.gameObject);
		}

	}

I am not getting any errors from the script. Anyone that can help, I would be thankfull.

If the box collider is set to trigger, then you need to use OnTriggerEnter2D.