The condensation of 5,5'-diformyl-3,4,3',4'-tetramethyl-2,2'-dipyrrylketone (XIb) with 3,4,3',4'-tetramethyl-2,2'-dipyrrylmethae (XIVb) has produced meso-oxy-l,2,3,4,5,6,7,8-octamethylporphin in 63% yield. The tautomeric structure of this compound is discussed and its spectroscopic properties compared with an early intermediate in the oxidative breakdown of haemoglobin to give bile pigment.