In　this　paper,　a　promising　approach　is　studied　that　can　efficiently　mitigate　seismic　effects　on　a　frame　structure　by　coupling　it　with　an　protection　system.　Various　devices　are　employed　to　achieve　this　objective,　including　tuned　mass　dampers,　dynamic　mass　absorbers,　elastoplastic　dampers,　and　rocking　rigid　walls.　This　paper　delves　into　the　efficacy　of　a　vibro-impacting　nonlinear　energy　sink　in　reducing　seismic　effects　on　a　frame　structure.　More　precisely,　a　supplementary　apparatus,　consisting　of　an　auxiliary　structure　equipped　with　a　vibro-impacting　nonlinear　energy　sink,　is　rigidly　linked　to　the　first　story　of　the　targeted　frame　structure.　The　seismic　response　of　this　coupled　system　is　derived　through　a　dynamically　equivalent,　low-dimensional　model.　As　a　result　of　the　rigid　connection　between　the　frame　structure　and　the　protection　system,　the　low-dimensional　model　includes　only　three　degrees　of　freedom:　two　displacements　that　represent　the　motion　of　the　frame　structure,　which　is　rigidly　connected　to　the　external　structure,　while　the　third　characterizes　the　motion　of　the　vibro-impacting　mass.　For　the　vibro-impacting　nonlinear　energy　sink,　an　ideal　model,　which　assumes　instantaneous　impacts,　is　used　for　the　vibro-impacting　mass.　The　proposed　model　is　used　for　an　in-depth　parametric　analysis,　and　the　outcomes　are　presented　in　gain　maps　that　illustrate　the　effectiveness　of　the　coupling　within　a　designated　parameter　plane.　The　findings　demonstrate　that　the　coupling　with　the　external　structure,　which　is　equipped　with　a　vibro-impacting　mass,　effectively　mitigates　displacements　and　drifts　in　the　frame　structure　across　a　broad　range　of　parameter　values　that　define　the　protection　system.