Kansas City's American Multi-Cinema, Incorporated, who had opened the first In-Mall twin theatre in 1963, continued their cinematic innovation with the introduction of the world's first 4-screen operation or Multiplex. Known as the Metro Plaza 4, it opened, in Kansas City, Missouri, in 1966. It was a freestanding operation.

AMC's second multiple theater complex was built as part of Omaha, Nebraska's WESTROADS MALL. The Six West Theatres began business in January 1969. This In-Mall Shopping Mall Multiplex was followed by the NorthTown Six, at Dallas, Texas' NORTHTOWN MALL.

Simultaneously, AMC was also building 4-screen Shopping Mall Multiplex theaters. The earliest, an At-Mall installation known as the Fashion Square 4, was built at Southern California's LA HABRA FASHION SQUARE. It opened for business in August 1969.

This venue was followed by the Eastmont 4 Theatres, an In-Mall multiplex at Oakland, California's EASTMONT MALL. It showed its first features in August 1971. In August 1972, the world's first seven-screen multiplex, the Southwyck 7 Theatres, began business as part of Toledo, Ohio's SOUTHWYCK CENTER.

During the 1970s, previously-existing single and twin theaters were often hastily split into smaller multiple venues. These so-called "shoe box", or "cracker box", operations did much to diminish the motion picture viewing experience. Dividing a larger theater into two or three would require much smaller screens. Also, poorly-soundproofed partitions between auditoria often leaked sound between viewing rooms.