RE(OH)2.94(NO3)0.06·nH2O nanosquares were first employed as template to synthesize YVO4:Ln luminescent crystallites (Ln = Eu, Sm, and Dy) via hydrothermal nanoconversion in the presence of NH4VO3. Product properties and the course of phase/morphology evolution were characterized in detail by XRD, SEM, TEM, FT-IR, TG, and optical spectroscopy. It was clearly demonstrated that the nanosquares templated vanadate crystallization, owing to structure similarity, but was accompanied by subsequent dissolution and reprecipitation. The resultant vanadate phosphors, mostly in the form of bundles containing platelike and fibrous crystallites, exhibited strong red emission at ∼618 nm for Eu3+, orange-red emission at ∼604 nm for Sm3+ and greenish yellow emission at ∼575 nm for Dy3+ upon exciting the VO43− ligand. Dehydration at 500 °C further improved the emission by ∼2.5 times for Eu3+ and ∼1.5 times for Sm3+ and Dy3+. The Eu3+ (5 at%), Sm3+ (1 at%) and Dy3+ (1 at%) activators were analyzed to have quantum yields of ∼48, 9 and 16% and color coordinates of around (0.65, 0.33), (0.60, 0.39) and (0.38, 0.43) for their luminescence, and fluorescence lifetimes of ∼1.52, 1.40 and 0.89 ms for their dominant emissions, respectively. It is also interesting to find out that replacing only 15% of the total OH− and NO3− anions in the template by VO43− produced ∼20 times stronger Eu3+ luminescence, indicating that VO43-→ Eu3+ energy transfer is very efficient. The protocol would be extendable to other types of functional rare-earth compounds.