A principal objective of our work was to illustrate the existence of unknown trends in the E_CB=f(E_bg) and the E_VB=f(E_bg) behavior for certain classes of compounds that also included a set of bismuthate photocatalysts; new trends may easily be hidden within more general trends. Indeed, when the data for the bismuthates are added to data related to novel visible-light-active (VLA) photocatalysts, the trend remains the same with high significance levels for the E_VB=f(E_bg) linear correlation. Using well-known data for complex (ternary) oxides, the search for new trends in the behavior of the E_CB=f(E_bg) and the E_VB=f(E_bg) dependences opens up the potential to develop new VLA photocatalysts. The feasibility of new desired trends can be estimated a priori using a modern theoretical analysis of the electronic structure of targeted semiconductors; note that new trends in the behavior of E_CB and E_VB versus bandgap energy E_BG have been established for CaBi₆O₁₀, Sr₂Bi₂O₅, Sr₃Bi₂O₆, and Sr₆Bi₂O₁₁. We also re-examined earlier symmetric-type plots for a set consisting of a large number of simple (binary) and a set consisting of complex (ternary) metal oxides and find some significant differences. We herein report a novel trend in the empirical dependence of the energy positions of conduction bands (E_CB) and valence bands (E_VB) on bandgap energies (E_bg) for alkali earth metal bismuthate semiconductor photocatalysts for which we show that their dependences follow the linear functions E_CB=A+BE_bg and E_VB=a+bE_bg. However, contrary to earlier symmetric relationships of some metal oxides for which A=a=1.23 eV, B=−0.5, and b=0.5 toward water splitting, the relationships found for the bismuthates show them to be asymmetric with negative slopes (B<0, b<0) and a converging point A=a=4.5 eV. Also re-examined are the earlier symmetric-type plots for a set consisting of a large number of simple (binary) and a set consisting of complex (ternary) metal oxides and find some significant differences. Variations in both slopes (B<0 and b>0) and the converging point (1.4 eV<A=a<2.0 eV) is demonstrated. The photoactivity of some strontium bismuthates is predicted toward the photoelectrochemical reduction of CO₂ from the novel trend in behavior of their bands’ energy positions relative to their bandgap energies.