The syntheses, structures, and characterization (IR, TGA/DTA, UV/visible spectroscopy) of an isostructural family of layered coordination networks containing divalent metal ions (Co2+, Zn2+, and Cd2+), formate (ft) anions and neutral C3H8N2O2 ethyl carbazate (ec) ligands of formula M(ft)2(ec) are described. A manganese-containing compound with the same stoichiometry possibly adopts the same structure. Single-crystal structures of the zinc and cadmium phases show the presence of distorted ZnO5N and CdO5N octahedra, in which ec adopts N,O-bidentate coordination, and four monodentate ft anions bridge to adjacent metal ions. This connectivity leads to polymeric sheets built up from double octahedral layers propagating in the (001) plane. The crystal structures are completed by N–H ··· O and N–H ··· (O,O) hydrogen bonds. Crystal data: Zn(CHO2)2(C3H8N2O2), M r = 259.52, triclinic, (No. 2), a = 8.0848(2) Å, b = 8.7345(1) Å, c = 13.2841(3) Å, α = 74.2839(14)°, β = 86.7150(12)°, γ = 89.4713(15)°, V = 901.51(3) Å3, Z = 4, R(F) = 0.024, wR(F 2) = 0.056. Cd(CHO2)2(C3H8N2O2), M r = 306.55, triclinic, (No. 2), a = 8.4574(2) Å, b = 8.9112(3) Å, c = 13.5119(5) Å, α = 73.101(1)°, β = 86.366(2)°, γ = 89.420(2)°, V = 972.36(5) Å3, Z = 4, R(F) = 0.022, wR(F 2) = 0.053.