Instructional materials, such as printed textbooks and digital resources, are a cornerstone of education in kindergarten through grade 12 (K-12) education and represent a powerful lever for improving classroom instruction. Historically, the selection of instructional materials in the United States has been predominantly led by local school districts, allowing material selection to be tailored to the specific needs of students and educators. Although this decentralized approach is intended to ensure local alignment, critics argue that it creates inefficiencies, neglects best practices, and contributes to disparities in instructional quality across districts. Over the past two decades, state education agencies (SEAs) have increasingly expanded their roles in this process, encouraging the adoption of state-approved instructional materials and aligned professional learning (PL) opportunities to improve instructional quality and better align materials with state standards. The Council of Chief State School Officers' (CCSSO's) High-Quality Instructional Materials and Professional Development (IMPD) Network provides member states with several resources, including a dedicated coach, structured in-person convenings guided by IMPD leadership, and opportunities for peer learning to promote the use of HQIM in their states. This report presents thorough documentation of how the IMPD Network supports the work of policymakers in their member states and whether these efforts have translated to increased access to high-quality instructional materials (HQIM) and high-quality PL (HQPL) opportunities for teachers in their states.