N-Heterocycle-fused Ni(ii) porphyrin dimers upon heating of meso-amino Ni(ii) porphyrins in nitrobenzene

Simple refluxing of amino Ni( ii ) porphyrins 5 and 6 in nitrobenzene gave fused porphyrin dimers 9 and 11 with roughly coplanar structure. Q-like bands of the resulting 2,6-naphthyridine-fused porphyrin dimers are significantly red-shifted.