Highly confined lead halide perovskite nanomaterials, like perovskite quantum dots (PQDs) and other novel nanoclusters (PNCLs) have attracted attention owing to their superior optoelectronic properties and have great potential in fields like light-emitting diodes (LEDs), photodetectors, solar cells, and even now, quantum information processing. Despite their encouraging potential, PQDs exhibit optical and spin-optical performance degradation that can be due to chemical and structural instability that is strongly correlated to the presence of defects and electron-phonon interactions. Although extensive research has been done on the degradation in correlation to performance, in-depth experimental studies of defect and electron-phonon interactions influences on physical processes, such as electron spin relaxation and photoinduced charge separation and recombination, are generally lacking detailed mechanisms. The primary goal of this thesis is to reveal the optical and spin-optical dynamics and the role they play on material performance of novel lead halide perovskite nanomaterials. Precise chemical tuning of PQD structure, high-quality synthesis, QD passivation, and isotope enrichment, is an appropriate way to intuitively enhance the materials optical and spin-optical properties. Since charge carrier processes occur on femtosecond to microsecond time scales, sensitive time-correlated single photon counting and ultrafast pump-probe spectroscopic methods, such as time-resolved photoluminescence and femtosecond transient absorption, will be used to interrogate these physical processes. This method of tracking the photogenerated charge carriers will collect valuable information, like population densities and trap states near the band edges, that will be used to construct a kinetic model. This dissertation research will establish charge carrier mechanisms, identify electron-phonon coupling, investigate the influence of nuclear spin-electron spin interaction, and provide a window into how these phenomena affect material performance. This dissertation aims to establish a deeper intuition of the charge and spin carrier kinetics and provide insight into the structure-function relationships of multifunctional PQDs and other perovskite variants.