Abstract. The structures of two porphyrin-based metalorganic frameworks are reported. The reaction of a carboxylic acid functionalised porphyrin with Mn(NO 3 ) 2 gives rise to either a one-dimensional or a two-dimensional framework structure depending on the reaction solvent employed.562 (5) , P 1 1, R1 ¼ 0.0894, wR2 ¼ 0.2850) consists of one-dimensional coordination polymers linked through hydrogen-bonded porphyrin molecules leading to a twodimensional array. In contrast 2 (a ¼ 13.6852 (6) , P2 1 /c, R1 ¼ 0.1218, wR2 ¼ 0.3806) consists of two-dimensional sheets, constructed from dinuclear Mn(II) clusters and bridging porphyrin ligands, which, as in 1, are linked through hydrogen-bonded porphyrin molecules but in this case leading to a three-dimensional array. In both structures it is notable that the porphyrin molecules do not bind the Mn(II) cations through the macrocyclic carity, rather both structures.