Three novel complexes, namely, penta‐μ‐acetato‐bis(μ2‐2‐{[2‐(6‐chloropyridin‐2‐yl)hydrazinylidene]methyl}‐6‐methoxyphenolato)‐μ‐formato‐tetramanganese(II), [Mn4(C13H11ClN3O2)2(C2H3O2)5.168(CHO2)0.832], 1, hexa‐μ2‐acetato‐bis(μ2‐2‐{[2‐(6‐bromopyridin‐2‐yl)hydrazinylidene]methyl}‐6‐methoxyphenolato)tetramanganese(II), [Mn4(C13H11BrN3O2)2(C2H3O2)6], 2, and catena‐poly[[μ2‐acetato‐acetatoaqua(μ2‐2‐{[2‐(6‐chloropyridin‐2‐yl)hydrazinylidene]methyl}‐6‐methoxyphenolato)dimanganese(II)]‐μ2‐acetato], [Mn2(C13H11ClN3O2)(C2H3O2)3(H2O)]n, 3, have been synthesized using solvothermal methods. Complexes 1–3 were characterized by IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction. Complexes 1 and 2 are tetranuclear manganese clusters, while complex 3 has a one‐dimensional network based on tetranuclear Mn4(L1)2(CH3COO)6(H2O)2 building units (L1 is 2‐{[2‐(6‐chloropyridin‐2‐yl)hydrazinylidene]methyl}‐6‐methoxyphenolate). Magnetic studies reveal that complexes 1–3 display dominant antiferromagnetic interactions between MnII ions through μ2‐O bridges. In addition, 1–3 also display favourable electrochemiluminescence (ECL) properties.