Hexagonal-phase LaF3: Yb3+, Er3+, hexagonal-phase NaGdF4: Yb3+, Er3+, cubic-phase NaYF4: Yb3+, Er3+ nanocrystals (NCs), and hexagonal-phase NaYF4: Yb3+, Er3+ submicrorods (MRs) were prepared with oleic acid as capping ligand. The NCs and MRs can be redispersed in nonpolar organic solvents, thus forming transparent and stable solutions. Under a 980-nm excitation from a diode laser, the Yb3+, Er3+-codoped NC and MR colloidal solutions present bright green upconversion fluorescence.