We present a library of 39 open cluster optical/near-IR integrated spectra. The data were obtained at CASLEO (San Juan, Argentina) and LNA (Itajuba, Brazil). Eight additional spectra obtained at ESO (La Silla, Chile), also employed in the present analysis, are already available at CDS (see cat. <III/219>). The data were combined in order to derive high S/N templates of young and intermediate-age populations sampling their evolutionary states with unprecedented time resolution at nearly solar metallicity. These template spectra, also included in the library, are useful, e.g., for population synthesis techniques applied to galaxies and for estimates of individual cluster parameters in the Milky Way as well as in external galaxies.