Of the types of experimental phase diagrams available for ternary systems, isopleths are the least in number. In the past one reason might have been the resources needed to produce a single experimental diagram. However, with current computers and databases, predicted isopleths are as accessible as predicted isotherms and liquidus projections. Therefore it is worth giving a fresh look at isopleths and considering how they could be used in the future. To begin a brief review will be given of information available from isopleths. The information includes ZPF and SPB lines for each phase and the identification of miscibility gaps and invariant reactions. After the review a proposal will be given for how isopleths and polyisopleths could be used to give alloy and process designers a unique visual optimization tool when trying to increase or decrease solubility limits, processing temperatures, or amounts of selected phases.