Results of extensive quantum-chemical modeling of the gas-phase reactions during CVD of group 13-15 materials are discussed in the light of single-source precursor concept. Two quantitative parameters (donor-acceptor bond dissociation enthalpy and elimination reaction enthalpy) are introduced as criteria for the classification of potential candidates for the single-source precursors. Hydrogen-containing molecules are predicted to have higher importance as precursors for the stoichiometry-controlled CVD processes. Importance of the ring and cluster single-source precursors in the CVD of doped metal nitrides is emphasized. In contrast, P, As-containing precursors with metal-halide bonds are predicted to be inefficient.