A facile aqueous solution synthesis of La(OH)3 nanorods and La2O3 nanoplates, only using La(NO3)3·6H2O as the lanthanide source and formamide as the alkaline source at room temperature, is reported for the first time. After high temperature calcination, the 1D La(OH)3 nanorods evolved into 2D La2O3 nanoplates. A possible evolution mechanism during heat treatment was proposed. The photoluminescence (PL) characteristics of both La(OH)3 nanorods and La2O3 nanoplates were investigated with purple light under UV excitation, which showed potential applications in fluorescent devices.Highlights► La(OH)3 nanorods and La2O3 nanoplates were synthesized. ► After high temperature calcination, the 1D La(OH)3 nanorods evolved into 2D La2O3 nanoplates. ► Both the materials show specific photoluminescence (PL) characteristics. ► This synthesis route can be extended to the synthesis of other metal-oxide materials.