After World War II, business recovered strongly — partly due to the collapse of German lantern production, and partly due to high demand for safety lanterns along roads and railways.
In 1948, Dietz introduced the Comet, which became the official lantern of the Boy Scouts of America — the country's largest scouting organisation.
In 1950, Gerry (Gary) Dietz, son of Robert II, took over the business. In 1955, new regulations banned the use of kerosene lanterns along public roads, causing a significant drop in sales. Lanterns were now primarily used in locations without electricity. That same year, the Greenwich Village factory was closed.
Recognising the need for drastic action, Gerry opened R.E. Dietz Ltd. Hong Kong in 1957 to reduce production costs. This ultimately led to the closure of the Syracuse factory in 1970, with all production moved to Hong Kong. In 1967, Gerry's son John Dietz had already assumed leadership of the company.
Dietz continued to innovate relentlessly, outcompeting rivals or acquiring them outright. A growing portfolio of patents gave Dietz a powerful legal advantage, and numerous disputes and lawsuits followed. By acquiring competitors primarily for their patents and designs, Dietz steadily grew into the dominant force in the lantern industry.
In 1894, Robert E. Dietz's son Frederick (Fred) Dietz took over the company. Fred proved just as innovative as his father — he filed 25 new patents, designed the iconic Dietz logo, and expanded international sales significantly.
In 1897, Dietz suffered a major setback: the New York City factory burned to the ground, leaving only the four exterior walls standing. According to family accounts, Fred never told his father about the fire. Robert E. Dietz passed away that same year, just four months after the disaster — never knowing the factory had burned.