Potential of the inorganic rings and clusters as single-source precursors to 13-15 binary materials and composites is examined employing quantum-chemical methods. Importance of the gas phase association reactions during MOCVD processes from organometallic and hydride precursors is emphasized. Generation of the gas phase [HMYH]_n clusters (M=Al,Ga,In; Y=N,P,As) with large oligomerization degree (n ≥ 30) is thermodynamically favorable even at high temperature conditions (1000 K) for all M, Y pairs. High stability of the N-containing clusters makes mixed metal oligomer imidometallanes excellent single-source precursors for the stoichiometry-controlled MOCVD of 13-15 composites.