This invention relates to processes for a range of compounds, polymeric compounds, and compositions used to prepare semiconductor and optoelectronic materials and devices including thin film and band gap materials for photovoltaic applications including devices and systems for energy conversion and solar cells. In particular, this invention relates to polymeric precursor compounds and precursor materials for preparing photovoltaic layers. A compound may contain repeating units {MA(ER)(ER)} and {MB(ER)(ER)}, wherein each MA is Cu, each MB is In or Ga, each E is S, Se, or Te, and each R is independently selected, for each occurrence, from alkyl, aryl, heteroaryl, alkenyl, amido, silyl, and inorganic and organic ligands.