No OnCollisionEnter with 2D colliders?

I cant get OnCollisionEnter to work with objects with 2D colliders and Rigidbody2D. OnTriggerEnter works if collider set to trigger.

This object has 2D Colliders and a RigidBody2d. The colliding object as well.

		void OnCollisionEnter (Collision collision)
		{
				print ("Zombieboy Collision");
				var x = 0;
				switch (collision.gameObject.name) {
				case ("Martha(Clone)"):
						arrivedAtTarget = true;
						print ("Gotcha");
						break;
				default:
						break;

				}
		}

It’s OnCollisionEnter2D, I think (I haven’t used the 2d collision system yet).

Check the Messages section of Collider2D for details.