The preparation, crystal structures and magnetic properties of the copper(II) complexes of formula [Cu₂(tppz)(H₂O)₂(CF₃SO₃)₄] (1), [Cu(tppz)(CrO₄)]_n·3nH₂O (2) and [Cu₄(tppz)₄(H₂O)₄(MoO₄)₂](CF₃SO₃)₄·7H₂O (3) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine] are reported. Complex 1 is a dinuclear species where tppz adopts a bis-tridentate bridging mode with an intramolecular copper–copper separation of 6.5221(6) Å. Each copper(II) ion in 1 has an elongated octahedral geometry with three tppz nitrogen atoms and a water molecule in the equatorial positions and two triflate oxygen atoms occupying the axial sites. Complex 2 is a uniform copper(II) chain where the copper atoms are bridged by two oxygen atoms of the chromate group (μ_1,2-CrO₄), the value of the intrachain metal–metal separation being 4.2614(5) Å. Each copper(II) ion in 2 exhibits a somewhat distorted square pyramidal geometry with three nitrogen atoms from a tridentate tppz ligand and a chromate oxygen atom in the basal plane and an oxygen atom of a symmetry-related chromate group in the apical position. Complex 3 is a cyclic tetranuclear compound where peripheral [Cu(tppz)(H₂O)]²⁺ units are connected through two molybdate groups, each one adopting the μ_1,1,2-MoO₄ bridging mode. Regular alternating five [Cu(1) and Cu(4)] and six [Cu(2) and Cu(3)] coordinated copper(II) ions occur in 3 with distorted square pyramidal CuN₃O₂ and elongated octahedral CuN₃O₃ surroundings, respectively. The four copper atoms in 3 have in common the presence of a molybdate-oxygen and three tppz-nitrogen atoms in the basal [Cu(1) and Cu(4)]/equatorial [Cu(2) and Cu(3)] planes and a water molecule in the apical [Cu(1) and Cu(4)]/one axial [Cu(2) and Cu(3)] positions whereas the remaining axial position is occupied by a molybdate-oxygen [Cu(2) and Cu(3)]. The shorter intramolecular copper–copper separation is 3.371(1) Å [Cu(2)⋯Cu(3)], the other ones varying in the range 5.537(1)–6.301(1) Å. The investigation of the magnetic properties of 1–3 in the temperature range 1.9–295 K has shown the occurrence of intermediate antiferro- [J = −48.0(1) cm⁻¹ with Ĥ = −JŜ₁·Ŝ₂ (1)], weak ferro- [J = +0.28(1) cm⁻¹ with Ĥ = −JΣ_iŜ_i·Ŝ_i+I (2)] and coexistence of weak ferro- and antiferromagnetic interactions [J₁ = +2.38(2) cm⁻¹, J₂ = +0.56(2) cm⁻¹ and J₃ = −1.53(2) cm⁻¹ with Ĥ = −J₁ (Ŝ₂·Ŝ₃) + J₂ (Ŝ₁·Ŝ₃ + Ŝ₂·Ŝ₄) + J₃ (Ŝ₁·Ŝ₂ + Ŝ₃·Ŝ₄) (3)] between the copper(II) ions across bis-tridentate tppz (1), μ_1,2-CrO₄ (2), di-μ_1,1-MoO₄ and μ_1,2-MoO₄ (3) bridges. The values of the magnetic interactions are analyzed in terms of simple orbital symmetry considerations and compared with those reported for parent systems.