Chemistry is, simply spoken, the science of making and analyzing compounds. As such, the synthetic aspect of chemistry is central to many endeavors in today's research, as the ability to synthesize a molecule is a prerequisite to its experimental analysis. Therefore, much of the work at the forefront of current research in the field is focused either on i) making novel compounds, ii) improving methodologies to access known compounds or structural motifs or iii) devising new methods for these purposes. The name of the game here is better, faster, cleaner, easier -i.e. more efficient. Indeed, the use of "efficient" as a descriptor of methods or procedures has become increasingly popular in the literature over the past two decades (Figure ). In 2019, around 10,000 papers across all major chemistry journals contained the word "efficient". Despite this popularity, a clear definition of the term efficiency in a chemical sense is missing from the literature.