Seven 25-litre bottles allegedly filled with the drug were found in a Holden Commodore after its driver was stopped by police last Thursday.
Police said subsequent testing confirmed the contents as being 1,4-Butanediol, also known as GBL or Liquid Ecstasy or Fantasy.
The find led to a search warrant being executed on a residence in Penshurst at about 3pm (AEDT) on Saturday.
A further container was seized from the location, as well as $28,000 in cash and drug paraphernalia, police said.
The estimated potential street value of the drugs seized is between $875,000 and $1.1 million.
A 30-year-old man from Penshurst has been charged with one count of supplying a large commercial quantity of a prohibited drug.
He was refused bail when he appeared in Parramatta Bail Court on Sunday and will reappear in Central Local Court on the January 8.