Rect.Rect  

var rect = Rect (0, 0, 10, 10);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Rect rect = new Rect(0, 0, 10, 10);
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public rect as Rect = Rect(0, 0, 10, 10)