The trend towards large glass façades and the urge to reduce the material to a minimum requires further evolution in high performance transparent as well as lightweight structures. Therefore, a combination of polymeric interlayer core, chemically connected to cover layers of thin glass to reduce self-weight and to utilize the high durability of glass at the same time, is under development. The novel glass–plastic-composite panels behave as a unit and ensure a sufficient and high-performance load-bearing behaviour. The first studies, including four-point bending tests according to EN 1288-3 (2000), showed a nearly equivalent load-bearing behaviour to monolithic glass panes with the same nominal thickness. However, the composite load-bearing behaviour is significantly influenced by time- and temperature-dependent stiffness of the polymer interlayer material, as well as the shear connection between the interlayer core and glass cover layers. Hence, an extended experimental study on the load-bearing behaviour of the innovative composite panels was performed. This paper presents the new product with possible applications for the building industry and introduces the ongoing development and investigation process for the novel glass–plastic-composite panels. Afterwards, the test methods and results for the conducted short- and long-term four-point bending tests are given. Subsequently, the behaviour of the composite panels is compared to conventional glass, and the insights are discussed. This also includes a study on potential material models and analytical simulations to extend the results to large-scale application. The high structural performance and lower self-weight at the same time paves the way for high transparent glass construction with slender substructures.