The title compounds, bis(dimethylformamide)-1 kappa O,3 kappa O-bis[mu-2,2'-[2,2'-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenolato]-1 kappa(4)N,N',O,O':2 kappa(2)O,O';2 kappa(2)O,:3 kappa(4)N,N'prime prime or minute,O,O'-di-mu-nitrito-1:2 kappa(2)N:O;2:3 kappa(2)O:N-dinickel(II)cobalt(II), [CoNi(2)(NO(2))(2)(C(19)H(22)N(2)O(2))(2)(C(3)H(7)NO)(2)], (I), -copper(II), [CuNi(2)(NO(2))(2)(C(19)H(22)N(2)O(2))(2)(C(3)H(7)NO)(2)], (II), and -manganese(II), [MnNi(2)(NO(2))(2)(C(19)H(22)N(2)O(2))(2)(C(3)H(7)NO)(2)], (III), consist of centrosymmetric linear heterotrinuclear metal complexes. The three complexes are isostructural. There are three bridges across the Ni-M atom pairs (M is Co(2+), Cu(2+) or Mn(2+)) in each complex, involving two O atoms of a mu-N,N'-bis(salicylidene)-2,2'-1,3-propanediaminate ligand and an N-O moiety of a mu-nitrito group. The coordination sphere around each metal atom, whether Co(2+), Cu(2+), Mn(2+) or Ni(2+), can be described as distorted octahedral. The Ni...M distances are 2.9988 (5) A in (I), 2.9872 (5) A in (II) and 3.0624 (8) A in (III).