Decabromodiphenyl ether is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers (PBDEs).

Dehydroacetic acid is a pyrone derivative used mostly as a fungicide and bactericide. It is used to reduce pickle bloating as a preservative for squash and strawberries. Also used in antienzyme toothpastes.

3,3'-Diaminobenzidine (DAB) is an organic compound. This derivative of benzidine is a precursor to polybenzimidazole fiber. As its water-soluble tetrahydrochloride, it has been used in immunohistochemical staining of nucleic acids and proteins.

Diazomethane is the chemical compound CH₂N₂. It is one of the most common diazo compounds. In the pure form at room temperature, it is a famously explosive yellow gas. Diazomethane is always prepared as needed as a solution in ether and used as such.

Methylamine is an organic compound with formula CH₃NH₂. This colourless gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine.

Diisoheptyl phthalate is a phthalate used as a plasticizer. Diisoheptyl phthalate is typically a mixture of chemical compounds consisting of various isoheptyl esters of phthalic acid with the chemical formula C₂₂H₃₄O₄.

N,N-Dimethylaniline (DMA) is an organic chemical compound, a substituted derivative of aniline. It consists of a tertiary amine, featuring dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but commercial samples are often yellow. It is an important precursor to dyes such as Crystal violet.

2,4-Dichlorophenoxyacetic acid (2,4-D) is a common systemic pesticide / herbicide used in the control of broadleaf weeds. 2,4-D is a synthetic auxin (plant hormone), and as such it is often used in laboratories for plant research and as a supplement in plant cell culture media such as MS medium.

Diethylenetriamine (DETA) is a colourless hygroscopic liquid , soluble in water and polar organic solvents. It is a structural analogue of diethylene glycol. Its chemical properties resemble those of ethylene diamine, and it has similar uses. It is a weak base and its aqueous solution is alkaline.

Deoxyribonucleic acid or DNA, is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms (with the exception of RNA viruses). The main role of DNA molecules is the long-term storage of information.

Cypermethrin is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes. It behaves as a fast-acting neurotoxin in insects.

p-Xylene is an aromatic hydrocarbon, based on benzene with two methyl substituents. It is an isomer of xylene. p-Xylene is used on a large scale for the manufacture of terephthalic acid. Its polymer is known as Parylene.

Dimethylmercury is an organomercury compound. This colourless liquid is one of the strongest known neurotoxins. It is described as having a slightly sweet smell, although inhaling enough vapour to detect its odour is hazardous.

Direct Blue 1 is an organic compound with the chemical formula C34H28N6O16S4, used as a dye.

Cytosine (C) is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2).

Dioxathion, systematically known as p-dioxane-2,3-diyl ethyl phosphorodithioate, is an organophosphate pesticide. It is used as an insecticide on livestock and as an acaricide on citrus fruits, deciduous fruits and nuts.

DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a herbicide that inhibits photosynthesis. DCMU is a very specific and sensitive inhibitor of photosynthesis. It blocks the plastoquinone binding site of photosystem II.

Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both the vertebrates and invertebrates.

Dithranol is a Hydroxyanthrone, anthracene derivative, medicine applied to the skin of people with psoriasis.

Dicofol is an organochlorine pesticide that is chemically related to DDT. Dicofol is a miticide that is very effective against red spider mite.

Dichlorodifluoromethane is a chlorofluorocarbon halomethane (CFC), used as a refrigerant and aerosol spray propellant.

Diethylene glycol (DEG) is an organic compound with the formula (HOCH₂CH₂)₂O. It is a colourless, practically odourless, poisonous, and hygroscopic liquid with a sweetish taste. It is miscible in water, alcohol, ether, acetone and ethylene glycol. DEG is a widely used solvent.

Ethylenediaminetetraacetic acid, widely abbreviated as EDTA is a polyamino carboxylic acid and a colourless, water-soluble solid. It is widely used to dissolve limescale. Its usefulness arises because of its role as a hexadentate ligand and chelating agent, i.e., its ability to sequester metal ions such as Ca²⁺ and Fe³⁺.

Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect.

Ephedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia.