Solution-processed materials have significant promise for future generation solar cells. We will discuss our efforts to understand charge transport and carrier lifetimes as a function of structure in two classes of materials for thin film solar cells – organic semiconductors and hybrid organic metal halides. Organic bulk heterojunction (BHJ) solar cells have a complex structure where an electron donor and acceptor meet in a bicontinuous network with nanoscale dimensions. The development of non-fullerene acceptors has led to prospects for improvement of their power conversion efficiency through reduced losses in the open circuit voltage. We will discuss recent work to understand the origin of these effects in non-fullerene acceptors. Hybrid organic metal halides, such as CH3NH3PbI3, have garnered significant attention because they are earth-abundant, solution-processable materials that can be used to form solar cells with high power conversion efficiency (>20%). An interesting feature of these compounds is the ability to form layered Ruddlesden-Popper phases with quantum confinement by judicious choice of mixed organic cations. We will present our work on understanding the electronic properties of 3D and 2D organic metal halides using Pb- and Bi-based systems using techniques such as time-resolved microwave conductivity. We will also describe our efforts to characterize and control the phase behavior in thin films of layered Ruddlesden-Popper compounds, (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (n = 1, 2, 3, 4) towards high stability devices. Despite structural disorder apparent from quantitative analysis of grazing incidence X-ray scattering and electron microscopy, these materials surprisingly still have sharp band edges. The implications of these studies suggest that there is still much to be learned from these exciting materials systems.