The design and implementation of an advanced guided-inquiry experiment for the organic laboratory is described. Grubbs's second-generation catalyst is used to effect the ring-closing metathesis of diethyl diallylmalonate. The reaction is carried out under an inert atmosphere at room temperature and monitored by argentic TLC. The crude reaction is purified with activated carbon, and the product is analyzed using GC-MS and [superscript 1]H, COSY, [superscript 13]C, and DEPT-135 NMR. Additionally, a guided-inquiry approach is employed wherein students design a procedure to determine the influence of various parameters on the progress of the reaction and the purity and yield of the product. Student and instructor assessment of the advantages and challenges of using this approach are included. (Contains 2 tables, 1 figure, 1 scheme and 3 notes.)