Complex sentence: In 1962, Osco's headquarters was moved from Chicago's Merchandise Mart to Melrose Park, Illinois and the first side-by-side "Jewel-Osco" store opened.
Split into simpler sentences: In 1962, Osco's headquarters was moved from Chicago's Merchandise Mart to Melrose Park, Illinois. It was also in that year that the first side-by-side "Jewel-Osco" store opened.