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The cuprate superconductors are a classic example of correlated materials, where the sizable onsite Coulomb interaction on the copper 3$d$ orbitals is comparable with the kinetic energy of the electrons. Since the family of compounds exhibits the highest known superconducting transition temperatures at ambient pressure (superceded only by H$_3$S at extremely high pressures), they have been intensely studied since their discovery in the mid 1980s. Here, rather than pursuing low-energy model hamiltonians, we took a chemical approach and asked how could the chemistry of the materials be leveraged to tune superconductivity.  \emph{Electronic structure} -- We asked what chemical parameters very across the cuprates to give transition temperatures ranging from below 40K to over 130K. Based on a combination of first principles calculations and dynamical meaning field mean-field  theory to directly model the superconducting state, we found that varying the charge transfer energy tunes superconductivity. Specifically, LSCO has the largest charge transfer energy and a small Tc. Moving across the cuprate family we found that as the charge transfer energy was reduced, the transition temperature increased. Inspired by this finding, we sought to design a new family of cuprates with reduced charge transfer gaps in hopes of finding higher transition temperatures. Work by Zanaan, Sawatzsky and Allan showed that the relative alignment of the oxygen 2$p$ and copper 3$d$ orbital levels combined with the magnitude of the onsite repulsion $U$ controls the charge transfer energy. Dynamical mean-field calculations corroborated this picture by showing how the spectral charge transfer energy varies with the underline underlying  parameters of the hamiltonian. Additionally, density functional theory showed that the distance of the apical oxygen from the CuO$_2$ plane there is a charge transfer energy. Since we wanted to reduce the charge transfer energy to produce higher Tc's, we replaced the apical oxygen with sulfur, reasoning that its more extended 3$p$ orbitals would screen and reduce the strength of the in plane correlations. \emph{Structure prediction} -- We chose the $T$-type layered perovskite La$_2$CuO$_4$ as the starting point. Our intuition led us to propose the site substitution of the apical oxygen with sulfur. Due to the larger ionic radius of sulfur as compared to oxygen, we expect that the LaS charge reservoir layer to be crowded. To compensate, we explored the effect of substituting the large La ion with smaller trivalent ions $R$, selected from the lanthanide-like elements. The compositions we considered were $R_2$CuO$_2$S$_2$ (shown in Fig.~\ref{fig:rcuso}) and $R_2$CuO$_3$S. We include the monosulfide in hopes that the configurational entropy of only replacing a quarter of the apical oxygens with sulfur would help stabilize the target phase.