The chemistry of mixed heteroarene oligomers is an area of heterocyclic chemistry which remains to be explored in detail . I 4 Apart from Kauffmann's pioneering work,' there has been little development. While mixed heteroarene dimers are common in the literature,5--7 there is little information on mixed heteroarene trimers, and much less on higher oli- gomers, especially when the heteroarene components are all different, or connected at different positions. 12.7 ...