Seismic response of multi-storied base-isolated building on various isolation systems connected using viscous dampers to an adjacent dissimilar base-isolated or fixed-base building is investigated. The multi-storied buildings are modeled as a shear type structures with lateral degree-of-freedom at each floor, which are connected at different floor levels by the viscous dampers. Performance of this novel combination is studied by deriving the governing equations of motion and solving it in the incremental form using Newmark's step by-step method of integration. The variation of top floor absolute acceleration and bearing displacement under different real earthquake ground motions is computed to study the behavior and effectiveness of the connected systems. It is concluded that connecting the two adjacent base-isolated buildings with the viscous dampers is helpful in controlling large bearing displacement in the base-isolated structures; thereby, eliminating isolator damages arising due to instability at large displacement or pounding with adjacent structures during the earthquakes. Parametric studies are also performed to identify optimal parameters such as damper damping and distribution pattern of viscous dampers to achieve the maximum response reduction in the damper-linked adjacent buildings. The connection of viscous dampers to adjacent structures are found to be most effective when: (i) the adjacent base-isolated and fixed-base buildings are connected, (ii) dissimilar isolation systems are used for the two adjacent buildings, (iii) the time periods of adjacent structures are well separated, and (iv) the superstructure flexibility is higher.