A method for depositing copper-based films and a copper source precursor for use in the chemical vapor deposition of copper-based films are provided. The precursor includes a mixture of at least one ligand-stabilized copper (I) .beta.-diketonate precursor; and at least one copper(II) .beta.-diketonate precursor. The method includes introducing into a deposition chamber: (i) a substrate; (ii) a copper source precursor in a vapor state including a mixture of at least one ligand-stabilized copper (I) .beta.-diketonate precursor; and at least one copper(II) .beta.-diketonate precursor; and (iii) at least one transport gas, different than said copper source precursor. The reaction substrate temperature is maintained at from about 50.degree. C. to about 500.degree. C. for a period of time sufficient to deposit a copper-based film on said substrate.