Public Function min&(a As Range, b As Range, c As Byte)
Dim a_min&, b_min&
    If c =  0  Then 'minimum row requared
        a_min = a.Row: b_min = b.Row
    Else 'minimum column requared
        a_min = a.Column: b_min = b.Column
    End If
    If a_min > b_min Then min = b_min Else min = a_min
End Function

Public Function max&(a As Range, b As Range, c As Byte)
Dim a_max&, b_max&
    If c =  0  Then 'max row requared
        a_max = a.Cells(a.Cells.Count).Row
        b_max = b.Cells(b.Cells.Count).Row
    Else 'max column requared
        a_max = a.Cells(a.Cells.Count).Column
        b_max = b.Cells(b.Cells.Count).Column
    End If
    If a_max > b_max Then max = a_max Else max = b_max
End Function


Sub test()

    Debug.Print _
    Range(Cells(min([C12:C16], [D11:H11],  0 ), min([C12:C16], [D11:H11],  1 )), _
            Cells(max([C12:C16], [D11:H11],  0 ), max([C12:C16], [D11:H11],  1 ))).Address

End Sub