Crystal engineering in the development of improved pesticide products

Pesticides might be the only group of poisonous chemicals that are widely sprayed into the environment, but the use of pesticides is inevitable for crop protection and infectious disease control. When an ideal new pesticide compound is selected, its properties must be optimized to realize the full potential of the compound and extend its lifespan in the market. Crystal engineering has proven to be a viable strategy for manipulating the properties of solid-state pesticides. This review describes basic concepts of crystal engineering and its application in pesticide development through representative cases reported mainly by large agrochemical companies. The solid forms that present improved properties could justify patent protection, extending the market exclusivity of the pesticide product. The purpose of this review is to present the potential impact of crystal engineering strategies on the improvement of pesticide products, with emphasis on the importance of comprehensive characterization of the crystallization behaviors of a selected pesticide during its entire life cycle.