Left: direct gas-phase O/H vs. z measured in 19 CECILIA galaxies. The color of the circles represents the number of direct T_e measured in each galaxy: red circles have two or more direct T_e; yellow circles have a single T_e. The solar O/H ratio is plotted as a dashed green line and shaded area. While the highest-z galaxies tend to show low O/H, several CECILIA galaxies show gas-phase O/H consistent with the solar ratio at z ≳ 2. Right: the N2-BPT is reproduced with the T_e sample, color-coded by 12 + log(O/H). The CECILIA sample follows the expected trends in this relation: galaxies with low [N II]/Hα and high [O III]/Hβ exhibit relatively low O/H, and O/H increases with [N II]/Hα as [O III]/Hβ decreases.