How to fade out two gameObject instantly???,

I am new to Unity and C# coding. Here's my problem - i have fade out script and i use StartCoroutine and IEnumerator function to fade out an object but i want to fade out two object instantly. i tried some coding and i don't know why is it not working even though it work on first object but second object do not fade out:

 private IEnumerator CheckMatch()
     {
         if(_firstRevealed.id == _secondRevealed.id)
         {
             _score++;
             scoreLabel.text = "Score: " + _score;
             rend = _firstRevealed.GetComponent<SpriteRenderer>();
             rend1 = _secondRevealed.GetComponent<SpriteRenderer>();
             startFading();
             
             if (_score == 6)
             {
                 SceneManager.LoadScene("Menu");
             }
         }
         else
         {
             yield return new WaitForSeconds(0.5f);
 
             _firstRevealed.Unreveal();
             _secondRevealed.Unreveal();
         }
 
         _firstRevealed = null;
         _secondRevealed = null;
     }
 
     IEnumerator FadeOut1()
     {
         for (float f = 1f; f >= -0.05f; f -= 0.05f)
         {
             Color c = rend.material.color;
             Color c1 = rend1.material.color;
             c.a = f;
             c1.a = f;
             rend.material.color = c;
             rend.material.color = c1;
             yield return new WaitForSeconds(0.05f);
         }
     }
 
 
     public void startFading()
     {
         StartCoroutine("FadeOut1");
     }