These pills were marketed and sold under the radar to compete with Ecstasy, a Class-B drug, in the Auckland dance and nightclub scene.
Chase claimed he thought the pills were legal as 4-MMC was not specifically banned under the Misuse of Drugs Act.
However, a covert police investigation, Operation Ark, targeted London Underground and Chase was among 23 people arrested in November 2011.
The police alleged the London Underground tablets were not legal and in fact were analogues, or "substantially similar" in molecular structure, to illegal drugs.
Name suppression has lapsed for Chris Chase more than six years after he was arrested in Operation Ark. Photo / Richard Robinson
This was part of a worldwide phenomenon where chemists were tweaking the chemicals to skirt the boundaries of the law, the police alleged.
The jury decided both 4-MMC and 4-MEC were "substantially similar" to methcathinone, a Class-B drug, which made them analogues.
Analogues are considered Class-C drugs and in sentencing Chase to 10 years in prison, Justice Peter Woodhouse said the street value of pills sold was nearly $50 million.
The jury found 4-MMC and 4-MEC are analogues of methcathinone, a Class-B drug. Photo / Supplied
"This was the largest Class-C drug importation and dealing operation that has come before the New Zealand courts," said Justice Woodhouse, "and the largest by a very long way."
"Your role in this offending was pivotal ... London Underground, at least in New Zealand, was you."
The Herald can now reveal Chase was also charged with other analogue offences, using different powders from China, while on bail for Operation Ark.
This second investigation in 2012 was called Operation Greenstone.
However, multiple trials for Greenstone and Ark were put on hold while Chase and others appealed the convictions all the way to the Supreme Court.
A landmark Supreme Court ruling in 2017 upheld the convictions and effectively ruled out the defence relied on by Chase and others.
This led to a string of guilty pleas and sentencings this year - nearly seven years after Chase was first arrested.
For all that time, his identity has been kept secret to protect his rights to a fair trial.
But name suppression fell away today in the High Court at Auckland when he was sentenced on the Operation Greenstone charges.
He pleaded guilty to 7 charges of importing a controlled drug, as well as charges of conspiracy to import, possession to sell, and selling Class-C drugs.
His lawyer Ron Mansfield quoted lyrics from a hit by The Clash - "I fought the law and the law won"- in reference to his client.
He said London Underground was one of a number of companies selling compounds which were not specifically listed in the Misuse of Drugs Act.
Chase had sought legal opinions from three lawyers, said Mansfield, and Chase was confident in his interpretation of the law.
While this was arrogant, Mansfield said this is why Chase did not believe the drugs to be illegal -despite being arrested in Operation Ark - and offended while on bail.
However, this was considered to be an aggravating factor in the sentencing hearing.
Justice Geoffrey Venning effectively added an extra two years and six months in prison, on top of the 10 years Chase received for Operation Ark.
"You ran a sophisticated, commercial operation. By dealing in drugs, you took a business risk and now have to pay the price."
Craig Williams pleaded guilty to laundering $1.4 million in cash on behalf of Chase and conspiracy to import a Class-C controlled drug.
He was sentenced to home detention for 12 months.
Detective Inspector Bruce Good with some of the pills seized during Operation Ark in 2011. Photo / Sarah Ivey
Some of the pills seized during Operation Ark in 2011. Photo / Sarah Ivey
Cash seized in Operation Ark. Chris Chase and others made millions of dollars. Photo / Sarah Ivey
The London Underground saga
2001: Chris Chase and Lee Vincent start importing BZP and sell the first "legal high" party pills in NZ.
2008: BZP banned as a Class-C drug. Turn to mephedrone (4-MMC) from China as the new active ingredient.
2010: Police start Operation Ark to investigate pills mimicking Ecstasy.
2011: Chase among 23 arrests from Operation Ark. Police claim 4-MMC and other compounds are not "legal highs" but analogues – or "substantially similar" in structure – to illegal drugs.
2012: Chase arrested, while on bail, for importing new compounds like alpha-PVP in Operation Greenstone.
2015: Jury finds Chase and others guilty of 69 charges of importing and selling Class-C drugs. The verdicts mean 4-MMC and 4-MEC are analogues.
2016: Chase appeals the findings, which puts all connected trials on hold. Court of Appeal upholds convictions.
2017: Chase appeals to Supreme Court but findings are upheld. Supreme Court decision means defendants in connected Operation Ark and Greenstone trials start pleading guilty.
2018: Chase pleads guilty to Operation Greenstone charges and sentenced.
Sentences for Operation Ark and Greenstone
2013 - Operation Greenstone
Allen Stubbington - 5 years 10 months (55 per cent discount for early guilty plea and giving evidence for Crown).