How to create a bounding box gizmo over an area?

I am randomly assigning an object to a point on the screen, inside a particular area defined by a maxX, minX and a maxY and minY.
Id like to create a box over this area so I can visualize where the points may occur during debugging.I assumed I could use a gizmo but it looks like I cant?
Is the only way I can accomplish this through the LineRenderer?
If so how would I define the Vector2's to represent the minX ,maxX and minY,maxY to create the box?
Does anyone have an example of how to define these 4 Vectors? (I think I need 4)

 

use debug.drawline