Nitrogen donor tetradentate ligands 4,4′-bipyridazine (bpdz) and pyridazino[4,5-d]pyridazine (pp) were prepared by inverse electron demand Diels-Alder cycloaddition reactions of 1,2,4,5-tetrazine. Examination of their behaviour towards silver(i) ions revealed a special potential of the ligands for the design of 3D coordination frameworks involving characteristic polynuclear and polymeric silver(i)-pyridazine motifs and multiple coordination of the ligands. Ag4(pp)5(ClO4)4 and Ag 4(pp)5(SiF6)(BF4) 2·4H2O adopt a unique 3D trinodal 4,4,5-connected topology based upon five-fold coordination of the metal ions and tetradentate bridging function of the organic modules. Complexes Ag3(L) 3(SO3CF3)3·nH2O and Ag4(L)3(X)4·nH2O (L = bpdz, pp; X = BF4-, 0.5SiF62-) illustrate formation of highly-connected frameworks incorporating trinuclear clusters as an origin of the net connectivity. In the carboxylate complexes Ag2(L)(RFCOO)2 (RF = CF3, C2F5, C3F7) the pyridazine and acido ligands act as complementary linkers for generation of 3D frameworks involving helicate motifs. Fused bicyclic pyridazine pp is a unique system combining very efficient σN-donor ability and pronounced π-acidity. The coordination frameworks commonly exhibit strong anion-π interactions, including unprecedented examples of double anion-π,π binding that occur between pyridazino[4,5-d]pyridazine as a double π,π-receptor for geometry complementary SiF62- anions.