Light-emitting organic nanofibers made of phenyl molecules like para-hexaphenyl (p-6P) and grown on muscovite mica form a model system well-suited for the study of optics in the sub-wavelength regime. We demonstrate that p-6P nanofibers can be grown with high control of the morphology of individual nanoaggregates and also of the mutual alignment of aggregates by the use of appropriate growth conditions and substrate surfaces. The nanofibers can be detached from the substrate, thus allowing one to study the optical response tinder a huge variety of fundamentally different conditions, from individual floating aggregates to dense bunches of interacting aggregates. We show examples of linear and nonlinear optical properties of the blue-light-emitting aggregates and mention possible applications in future submicrometer-sized optoelectronics.