This paper reviews the research progress of conjugated polymers containing nitrogen-nitrogen double-bond bridges

for example

azobenzene and azopyrrole compounds and their derivatives. The trans form of the azobenzene molecule has a planar structure

whereas in the cis form of azobenzene

phenyl rings are twisted around the C—N bonds. The π-conjugated structure of the azobenzene is affected by the substitution of the phenyl ring

which gives rise to the variation of the bond lengths and bond angles. The measured conductivity showed a distinct difference in the trans form and the cis forms of azobenzene. These apparent changes in conductivity were attributed to the switching of height of the molecules rather than to an internal structural modification leading to a modification of resistance. The insertion of an azo group between heterocyclic rings pronounces the complex exhibiting a broader absorption band and a lower optical band gap compared to azobenzene. Consequently

the heterocyclic azo conjugated dye is an excellent candidate to be used as the photoactive material for the bulk heterojunction photovoltaic devices. The conductivity and synthetic methods of conjugated azo polymers are described. The present research situation of electrical and photonic conductivity of azobenzene and our perspectives of the future development of conjugated azo containing polymer are also presented.