The ABC approach to the estimation of thermodynamic and physical properties of organic compounds is based on the contributions of Atoms and Bonds in the properties of Conjugate forms of a molecular structure. The method has successfully been applied to the estimation of properties of acyclic hydrocarbons. In this article, the approach is extended to the estimation of thermodynamic and physical properties of acyclic organic compounds which may contain nitrogen, oxygen, or sulfur. The estimated properties are standard enthalpy of formation, normal boiling point, standard enthalpy of vaporization, critical pressure, critical temperature, and critical volume. The ABC technique is more accurate than a typical group-contribution approach.