But what exactly does waste mean in this regard? Admittedly, some sort and amount of waste material is a natural byproduct of almost any chemical transformationbe it solvents, inorganic salts or undesired reaction products. A similar situation exists for monetary investment and time, as all syntheses require some financial effort and time to perform said transformation. As such, efficiency must be relative, since it requires some form of benchmark to compare the resource investment of a given method to. Herein, the nature of a transformation or target molecule must be considered to avoid a comparison of apples to oranges. Consequently, any method should only be compared to its peers which accomplish the same task. By this logic, methods for an entirely new type of transformation cannot be termed efficient since there is no benchmark to meet.