Soligor is a brand name owned by AIC International Inc. used for optics, flash units and other photographic accessories. The earliest record of the brand is from 1956, when the US distributor Allied Impex Corporation used used the brand name Soligor for cameras and lenses imported from Japan. Allied Impex Corporation founded a German subsidiary called A.I.C. Phototechnik GmbH in 1968, that became Soligor GmbH in 1993. This German company was still offering products under the Soligor brand as late as 2010, but its webpage has since been “under construction”.
As far as I know, Soligor has never manufactured its own equipment. The Soligor brand name has been used for equipment manufactured by many different OEMs. Because of this, Soligor-branded products has varied in quality and performance.