Abstract : Here, we summarize the accomplishments relating to generating combinatorial libraries using dip-pen nanolithography (DPN) that we achieved during this AFOSR grant. Through powerful technological advances, we were able to meet the aims laid out in the proposal. Our first objective was to universally control the transport of matter at the nanoscale to improve the capabilities of DPN. To this end, we performed a systematic study to understand the dynamics of ink transport while developing agarose- and matrix-assisted DPN for the deposition of arbitrary materials. We achieved our next goal -- individually inking pens in order to write patterns with multiple inks at once -- by directly depositing ink in a self-correcting manner onto individual pens via ink-jet printing. Our final objective was to synthesize combinatorial arrays on a surface for biological screening, and we have made great progress towards this by developing massively parallel cantilever-free scanning probe lithography techniques (polymer pen lithography, hard-tip soft-spring lithography) that enabled the creation of combinatorial arrays of biomolecules with defined feature size and demonstrated their utility in studying cell differentiation. Furthermore, we developed a method to generate combinatorial arrays of sub-5 nm single crystal nanoparticles that act as binding sites for single proteins or as catalysts.