Porphyrins have practical applications in electronics as LCD displays, catalysts, sensors and for solar energy conversion due to their characteristic photophysical properties. The function and efficiency of these molecules in devices is largely attributable to how the molecules are organized on surfaces. Although considerable research has been published regarding the self-assembly of thiol and silane self-assembled monolayers (SAMs), there are few investigations of the solution-phase assembly of porphyrins on different substrates. Unlike thiol and silane SAMs, which have strong interactions between alkane chains to drive the self-assembly of monolayers, porphyrins consist of a macrocyclic tetrapyrrole structure with various substituents. Strong pi-pi interactions between porphyrin macrocycles result in a stacked assembly, analogous to a stack of coins. Depending on the substituents attached to the core, molecules may adapt different arrangements on surfaces. By changing the lengths and composition of the peripheral groups it may be possible to direct the assembly of porphyrins into different orientations, such as a side-on assembly or into a co-planar, stacked orientation. Synthetic modifications of the macrocycle such as by altering the peripheral groups or chelated metal ions can generate various designed electrical, photoelectric or magnetic properties. Investigations using AFM can be applied to directly observe the surface structures which are formed by adsorption of porphyrins on flat surfaces such as Au(111), mica(0001) and graphite(111). Preliminary work with ex situ and in situ AFM investigations of porphyrin self-assembly will be presented, as well as our initial efforts with nanoscale lithography using porphyrins. Since the surface organization of porphyrins substantially affects the photonic and electronic properties of porphyrin films, understanding the self-organization and assembly of porphyrins on various surfaces is critical for optimizing the function of these molecules in device applications.