The aim of this research is to produce chemistry instructional materials in “group investigation cooperative†oriented for empowering thinking skills on colloidal system topic. The thinking skills are important for students as it is the foundation for enhancing the mastery of concepts needed in the 21st century. The feasibility of chemistry instructional materials is evaluated based on its validity and practicality. The completion lesson plan implementation and students’ activities are the indicators of chemistry instructional materials practicality. Design of developing instructional materials was four-D-model, consist of Define, Design, Develop, and Disseminate. Data of this research was analyzed by descriptives statistic. The written chemistry instructional materials were then validated through expert evaluation done by two experts of science before it is tested to the target students. The result of this research were: (1) The instructional materials were developed consist of lesson plan, students’ book, worksheets, assessment, and power point media; (2) The instructional materials in developing are valid with good category in construction, content, language, and empirical validity, so contain principles of group investigation cooperative; (3) The dissemination expressed feasibility the lesson plan by teacher is well, increased the students activities indicated by doing investigation, analyze the result investigation and presentation of final product are empowering students’ thinking skills.