Is there a way of using just basic gui.Buttons as toggles?

I have this script here:

if (GUI.Button (Rect (Screen.width - (Screen.width - 10),Screen.height - 70,60,60),"Monsters") || Input.GetKeyUp("v")){
		showMonsterButtons = true;

that i want the showMonsterButtons to be false when i click it again. how would i do this?

is this what you mean?

if (GUI.Button (Rect (Screen.width - (Screen.width - 10),Screen.height - 70,6
0,60),"Monsters") || Input.GetKeyUp("v")){
           if(showMonsterButtons) showMonsterButtons = false;
           else showMonsterButtons = true;