Single-crystal X-ray structures of stacked ionic assemblies of meso-tetrakis(N-alkylpyridinium-4-yl)porphyrin and meso-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4-) were revealed. The tetracationic porphyrin and the tetraanionic porphyrin stacked alternately in a J-aggregation manner to form an oblique columnar array. To the best of our knowledge, this is the first report on the detailed structure of 1:1 stacked assemblies of tetracationic and tetraanionic porphyrins.