[2] Syngenta was founded in 2000 by the merger of the agrichemical businesses of Novartis and AstraZeneca, and acquired by China National Chemical Corporation (ChemChina) in 2017.

Syngenta brands include Actara (Thiamethoxam), Agrisure (corn with Viptera trait), Alto (Cyproconazole), Amistar (azoxystrobin), Avicta, Axial, Bicep II, Bravo, Callisto, Celest, Cruiser (TMX, Thiamethoxam), Dividend, Dual, Durivo, Elatus, Fusilade, Force, Golden Harvest, Gramoxone, Karate, Northrup-King (NK), Proclaim, Revus, Ridomil, Rogers, Score, Seguris, S&G, Tilt, Topik, Touchdown, Vertimec and Vibrance.

[7][8] As of 2014[update], Syngenta's main competitors were Monsanto Company, BASF, Dow AgroSciences, Bayer CropScience and DuPont Pioneer.

[13] In February 2016, ChemChina, a Chinese state-owned enterprise, offered to purchase Syngenta for $43 billion (480 Swiss francs per share), a deal which the company "unanimously recommended to shareholders".

[14] In April 2017, the Federal Trade Commission, the Committee on Foreign Investment in the United States, and the European Commissioner for Competition approved of the acquisition.

[28] At the end of 2020, Syngenta Group announced the acquisition of Valagro, a manufacturer of biological crop protection products headquartered in Atessa, Italy.

"[41] In 2010, the US EPA approved insecticidal trait stacks including Syngenta's AGRISURE VIPTERA™ gene, which offers resistance to certain corn pests.

[41] In 2021 the company partnered with Hong Kong-based Insilico Medicine to develop "sustainable weedkillers" by using AI deep-learning tools.

[42] Syngenta brands include Actara (Thiamethoxam), Agrisure (corn with Viptera trait), Alto (Cyproconazole), Amistar (azoxystrobin), Avicta, Axial, Bicep II, Bravo, Callisto, Celest, Cruiser (TMX, Thiamethoxam), Dividend, Dual, Durivo, Elatus, Fusilade, Force, Golden Harvest, Gramoxone, Karate, Northrup-King (NK), Proclaim, Revus, Ridomil, Rogers, Score, Seguris, S&G, Tilt, Topik, Touchdown, Vertimec and Vibrance.

[50] Syngenta's contributions to U.S. federal candidates, parties, and outside groups totaled $140,822 during the 2018 election cycle, ranking it 20th on the list of companies in its sector.

The following year Syngenta filed suits against Monsanto and other companies claiming infringement of its U.S. biotechnology patents covering genetically modified corn and cotton.

[53] Syngenta was the defendant in a class action lawsuit by the city of Greenville, Illinois concerning the adverse effects of atrazine on human water supplies.

In June 2021, Syngenta paid $187.5 million to settle an unknown number of cases in Illinois and California, implicating the company's Paraquat herbicide as a cause of Parkinson's disease.

[61][62] In 2022, the Federal Trade Commission announced that it is initiating litigation against Syngenta, challenging certain US-based discount programs extended to their respective customers.

[65] In 2024 more than 5,000 Americans have active lawsuits against Syngenta, alleging ties between use of the paraquat herbicide product, Gramoxone, and the onset of Parkinson's disease.

[74] On 14 October 2008, Syngenta donated the 123-hectare station to the Agronomy Institute of Paraná (IAPAR) for research into biodiversity, recovery of degraded areas and agriculture production systems, as well as environmental education programs.

In November 2015, Judge Pedro Ivo Moreiro, of the 1st Civil Court of Cascavel, ruled that Syngenta must pay compensation to the family of Valmir Mota de Oliveira ("Keno"), who was killed in the attack, and to Isabel Nascimento dos Santos who was injured.

[75][76] In his sentence the judge stated that "to refer to what happened as a confrontation is to close one's eyes to reality, since […] there is no doubt that, in truth, it was a massacre disguised as repossession of property".

Legal counsel from the university responded that Hayes had acknowledged sending letters having "unprofessional and offensive" content, and that he had agreed not to use similar language in future communications.

[78] According to an article in the 10 February 2014, issue of The New Yorker, Syngenta's public-relations team took steps to discredit Hayes, whose research is purported to suggest that the Syngenta-produced chemical atrazine was responsible for abnormal development of reproductive organs in frogs.