Deprotonation of 1-benzoylacetone with excess lithium hexamethyldisilazide (LHMDS) or lithium diisopropylamide (LDA) resulted in a dilithium dianion-type intermediate, which underwent a Claisen-type condensation with substituted aromatic esters or an isatoic anhydride to afford unsymmetrical 1,3,5-pentanetriones or a cyclized heterocyclic product when the C-acylated intermediates contained a select ortho-substituted phenacyl pendant group. Spectral data indicated that a particular tautomer, a (1Z,4Z)-1-(4-aryl)-1,5-dihydroxy-5-phenylpenta-1,4-dien-3-one, resulted upon recrystallization of the linear products. Condensation-cyclization of the dianion-type intermediate with methyl thiosalicylate resulted in a phenacyl benzdheterocyclic thiopyranone and with 5-chloroisatoic anhydride in a phenacyl quinolinone. X-ray crystal analysis of several products afforded additional proof of structure, especially regarding which tautomer was isolated.