Silver-mediated base pairs applied to DNA represent a new biomacromolecular nanomaterial useful for generating nanodevices as ion sensors. Repotted herein is a full. quantum chemical study devoted to give further knowledge on the electronic and energetic properties of C-Ag-C and mixed C-Ag-A :mismatched base pairs. The B3LYP functional in conjunction with the dispersion effects (D3) has been applied. Single-point calculations have been also performed by using the M06-L functional. The investigation of their behavior has been extended to the duplex DNA modeled by the (dC-Ag-dC), and (dC-Ag-dA)(2) more complex systems. The solvent effect has been taken into account by the conductor-like screening model, COSMO. In the case of mixed C-Ag-A and (dC-Ag-dA)(2) systems, both the Watson Crick and Hoogsteen arrangements have been taken into account. Results show that for (dC-Ag-dA)(2) systems, the binding energies are almost double that of the corresponding values of C-Ag-A ones.