This systematic study has demonstrated the dramatic yet logical impact that the synthesis conditions can have on the properties of UiO-66. Seven potential pitfalls regarding sample ideality were investigated, affording the conclusion that the material systematically becomes more “ideal” when the BDC:Zr ratio and/or synthesis temperature are increased. Such gravitation toward ideality makes sense when one notes that linker deficiencies are the underlying cause of the majority of pitfalls. We suggest that increasing the synthesis temperature and/or BDC:Zr ratio shifts the solution equilibrium in favor of BDC-Zr bonds, aiding the “ironing out” of linker deficiencies. This approach ultimately yields “ideal” UiO-66 with unsurpassed thermal stability when the synthesis is performed with a 2:1 BDC:Zr ratio at 220 °C. Access the research article here.