Reactions between [Nb₆Cl₁₂(CN)₆]⁴⁻ and [Mn(salen)]⁺ in MeOH–H₂O solvent mixture led to the formation of a new compound: {[(Mn₂(salen)₂)][[Mn(salen)(H₂O)]_0.67[Mn(salen)(MeOH)]_1.33(Nb₆Cl₁₂(CN)₆)]}·1.7H₂O·2MeOH (1). Single crystal X-ray analysis has shown that 1 possesses 1D framework built of heterotrimeric supramolecular anions, {[Mn(salen)(s)]₂[Nb₆Cl₁₂(CN)₆]}²⁻ and [Mn₂(salen)₂]²⁺ phenoxo bridged dimers linked to each other through two cyanide ligands located in axial positions. When 1 was left in a methanolic solution of (Me₄N)⁺, its 1D framework was transformed into a 2D framework of the previously reported compound [Me₄N]₂[(Mn(salen))₂(Nb₆Cl₁₂(CN)₆))] (2) which has a 2D anionic 4,4-network built of [Nb₆Cl₁₂(CN)₆]⁴⁻ and [Mn(salen)]⁺ nodes linked by CN ligands (Zhou, Day and Lachgar, Chem. Mater., 2004, 16, 4870).¹Magnetic susceptibility measurements indicate that 1 exhibits weak antiferromagnetic interactions due to the phenolate-bridged out-of-plane Mn(III) dimers with J = −1.50(5) cm⁻¹. Thermal stability of 1 was studied.