GUIContent.none

Description

Shorthand for empty content.

    // Draws a button without any text.
    function OnGUI () {
        GUI.Button (Rect (0, 0, 100, 20), GUIContent.none);
    }

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void OnGUI() {
        GUI.Button(new Rect(0, 0, 100, 20), GUIContent.none);
    }
}