Efficient methodologies based on the nucleophilic addition- N-acyliminium ion cyclization and the parham-type cyclization sequences of N-phenethylimides 1 and 2 are reported for the synthesis of a variety of heterocyclic systems: benzo[a]quinolizidones and their 2-oxa analogs, isoindoloisoquinolones, dibenzo[a,h]quinolizidones, thiazolo-, oxazolo-, and imidazolo [4,3-a]isoquinolones.