Composite materials, which are used for dental restorations for more than 50 years are gradually replacing amalgams. Such dental composites have led to a breakthrough in modern dentistry since they are easy to manipulate, inexpensive and have excellent esthetic properties. Their organic matrix is mainly based on monomers such as dimethacrylates and additives (e.g. initiators, stabilizers, pigments). Before curing the monomer molecules are located at Van-der-Waals distance to each other, which changes during curing with the formation of covalent bonds. This causes a volumetric shrinkage during photocuring and has been a major challenge for research and industry. The resulting shrinkage stress is supposed to generate microleakage, marginal staining, secondary caries and post-operative sensitivity. Cyclic monomers like vinylcyclopropanes (VCPs) exhibit dramatically reduced shrinkage upon curing and can be a conceivable alternative to methacrylates for the development of low-shrinkage composites. In this study the synthesis of new difuncitonal VCPs 3-11 is described. The reactivity is studied with photo-differential scanning calorimetry using bis(4-methoxybenzoyl)diethylgermane (Ivocerin®) as photoinitiator. Real-time near-infrared photorheology measurements are performed to evaluate rheological behavior (i.e., time of gelation, polymerization-induced shrinkage force) and chemical conversion (i.e., double bond conversion at the gel point, final double bond conversion) of the vinylcyclopropanes in situ. Composites based on VCPs 3¿11 show good mechanical properties and exhibit significantly lower volumetric shrinkage and shrinkage stress than corresponding dimethacrylate-based materials.