Autonomously self-repairing and -healing processes will play a key role in the development of future ‘smart’ materials and devices. Here we present the development of a novel second generation Grubb's catalyst that can be activated through the application of mechanical force in solution as well as in the solid state. We show thorough kinetic analyses as well as extensive optimization for the improvement of the catalyst's activity and lifetime and have eventually translated the concept to the solid state. It could be successfully proven that mechanical activation initiates the ROMP to linear as well as cross-linked polymers in the solid state and by this we present for the first time the autonomous repair of a material that relies on the mechanochemical activation of catalysts on the molecular level. We are certain that this tailor-made prototypical catalyst-system establishes an important step for the implementation of self-healing materials in an everyday environment and are confident that this novel motif will stimulate future research on this field.