The fused bicyclic skeleton is an important subunit in many natural products, pharmaceuticals, and organic building blocks in organic synthesis (some examples are depicted here). Thus, it is not surprising that various new synthetic methods have been developed for their construction. Within this context, the Conia-ene reaction of an alkyne with an enolizable carbonyl group is a fundamental method for carbon-carbon bond formation and is widely used in carbocyclization reactions. For example, Nakamura [4a-c] and Toste [4g-i] have explored metal-catalyzed intramolecular Conia-ene-type reactions, providing a rapid route to a diverse range of carbocycles and heterocycles. The Nazarov cyclization is another very versatile method for the synthesis of five-membered carbocycles due to the stereospecific nature of the cyclization. Recently, mechanistic insights into this reaction and its synthetic applications in total synthesis have been well demonstrated by Trauner [6h-j] and Eisenberg and Frontier [6a-g] . In addition, domino reactions and one-pot tandem catalyses have shown their unrivalled power in organic synthesis due to their ability to merge several reactions into one operation. Herein, we report an efficient InA C H T U N G T R E N N U N G (OTf) 3 -catalyzed (OTf = trifluoromethanesulfonate), highly regio-and diastereoselective tandem reaction, featuring Nazarov-cyclization/Conia-ene-type reactions, that synthesizes fused bicyclic scaffolds from alkynyl dienones (Scheme 1). Furthermore, a concise one-pot strategy was successfully accomplished by combining these tandem reactions with a Knoevenagel condensation, which provides rapid and efficient access to fused bicyclic compounds from readily available b-ketoesters (1) and alkynyl aldehydes (2; Scheme 1). In this one-pot reaction, piperidinium acetate [a] Dr.