A method to derive explicit binary isotherms following the ideal adsorbed solution (IAS) theory is proposed. The method is applicable to any pair of single-component isotherms, as long as they fulfill a set of conditions, as described in this report. Examples of some isotherms fulfilling such conditions are: Langmuir, anti-Langmuir, Brunauer-Emmett-Teller (BET), and quadratic. Following the method proposed in this report, three previously unreported explicit binary isotherms, quadratic-BET, quadratic-Langmuir, and quadratic-anti-Langmuir, while following the IAS framework, could be derived. This work presents the method and the binary isotherms derived through this method.