This bilateral call funds German–Swedish collaborative R&D projects in the field of “Erforschung von Materie” (materials research and structural biology) that develop or significantly improve instruments, methods (hardware/software), and research techniques for neutron and synchrotron large-scale facilities. It is embedded in Germany’s ErUM programme and implements the long-standing Röntgen-Ångström-Cluster (RÅC) cooperation, reflecting joint commitments to European research infrastructures such as the European Spallation Source (ESS, Lund) and European XFEL (Schenefeld). Projects must be jointly carried out by German and Swedish groups and align with RÅC goals. Focus: instrument/method development at facilities (BESSY II, FLASH, PETRA III, European XFEL, MAX IV, ESRF; FRM II, ILL, ESS). Strong emphasis on early preparation for ESS user operations and exploitation of the first 15 instruments (e.g., sample environments, data pipelines). Use of ML/AI for standardized data reduction/analysis is encouraged. Demonstrate performance on a relevant scientific question; pure science without instrument/method innovation and routine operations are out of scope. Exclusive reliance on FRM II for cold neutrons is not prioritized. Consortia may include universities, non-university institutes, and companies/SMEs where essential. Cross-border mobility and junior PI leadership are welcomed. Sustainability, data management, Open Access and science communication are expected.