YF3 and YF3:Eu3+ mesoporous hexagonal nanocrystals were successfully synthesized via a simple hydrothermal process based on the in situ assembly of the as-synthesized YF3 and YF3:Eu3+ nanoparticles. The well defined mesoporous nanostructures are formed by phenanthroline assisted assembly of similar to 20 nm nanoparticles, and 2-4 nm pores are contained as indicated by N-2 adsorption-desorption studies. The obtained YF3:Eu3+ mesoporous hexagonal nanoplates show a significant photoluminescence intensity enhancement compared with other shaped YF3:Eu3+ nanocrystals. (C) 2011 Elsevier Inc. All rights reserved.