  We present Cu and Zn abundances for 38 FGK stars, mostly dwarfs, spanning a
metallicity range between solar and [Fe/H] =-3. The abundances were obtained
using Kurucz's local thermal equilibrium (LTE) model atmospheres and the
near-UV lines of CuI 3273.95 A and ZnI 3302.58 A observed at high spectral
resolution. The trend of [Cu/Fe] versus [Fe/H] is almost solar for [Fe/H] > -1
and then decreases to a plateau <[Cu/Fe]> =-0.98 at [Fe/H] <-2.5, whereas the
[Zn/Fe] trend is essentially solar for [Fe/H] >-2 and then slightly increases
at lower metallicities to an average value of <[Zn/Fe]> =+ 0.18. We compare our
results with previous work on these elements, and briefly discuss them in terms
of nucleosynthesis processes. Predictions of halo chemical evolution fairly
reproduce the trends, especially the [Cu/Fe] plateau at very low metallicities,
but to a lower extent the greater [Zn/Fe] ratios at low metallicities,
indicating eventually missing yields.
