Acenaphthene is a polycyclic aromatic hydrocarbon (PAH) consisting of naphthalene with an ethylene bridge connecting positions 1 and 8. An alternative name, 1,2-dihydroacenaphthylene, emphasizes that it is a hydrogenated form of acenaphthylene. It is a constituent of coal tar.

Acetone is an organic compound with the formula (CH₃)₂CO. Acetone is miscible with water and serves as an important solvent. Familiar household uses of acetone are as the active ingredient in nail polish remover and as paint thinner.

Adamantane is a colourless, crystalline chemical compound with a camphor-like odour. Adamantane molecules consist of three cyclohexane rings arranged in an armchair configuration. It is unique in that it is both rigid and virtually stress-free.

Acetaminosalol is an organic compound with the chemical formula C₁₅H₁₃NO₄. It is an esterfication product of salicylic acid and paracetamol.

Adiponitrile is an organic compound with the formula (CH₂)₄(CN)₂. This dinitrile, a viscous, colourless liquid, is an important precursor to the polymer nylon 66.

Acid Fuchsin is one of the dyes used in Masson's Trichrome Stain. This method is commonly used to stain tissue sections in the Histology Laboratory in order to distinguish muscle from collagen. The muscle stains red with the acid fuchsin, and the collagen is stained green or blue with light green SF yellowish or methyl blue.

Acridine orange is a nucleic acid selective fluorescent cationic dye useful for cell cycle determination. It is cell-permeable, and interacts with DNA and RNA by intercalation or electrostatic attractions respectively.

Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system.

Aminophylline is a bronchodilator. It is a compound of the bronchodilator theophylline with ethylenediamine in 2:1 ratio. The ethylenediamine improves solubility, and the aminophylline is usually found as a dihydrate.

Aliquat 336 (Stark's catalyst) is a mixture of C8 and C10 chains with C8 predominating. It is a quaternary ammonium salt used as a phase transfer catalyst and metal extraction reagent.

Amobarbital is a drug that is a barbiturate derivative. It has sedative-hypnotic and analgesic properties. It is a white crystalline powder with no odour and a slightly bitter taste.

Allyl propyl disulfide is an organic compound with the chemical formula C₆H₁₂S₂. It is a pale-yellow liquid with a strong odour, it is a main ingredient in onion oil and used as food additives and flavours.

Amiodarone is an antiarrhythmic agent (medication used for irregular heart beat) used for various types of tachyarrhythmias (fast forms of irregular heart beat), both ventricular and supraventricular (atrial) arrhythmias.

Anilazine is a pesticide used on crops. It is used for controlling fungus diseases which attack lawns and turf, cereals, coffee, and a wide variety of vegetables and other crops. It is also used for the control of potato and tomato leafspots.

Azulene is an organic compound and an isomer of naphthalene. Whereas naphthalene is colourless, azulene is dark blue.

Barbital , was the first commercially marketed barbiturate. It is a white crystalline powder and is used as a sedative and hypnotic especially in the form of its soluble salt, sodium barbital

Ethenzamide is a common analgesic and anti-inflammatory drug that is used for the relief from fever, headaches, and other minor aches and pains. It is a major ingredient in numerous cold and flu medications and many prescription analgesics.

Azo violet is used as a dye and a pH indicator. It forms blue colour with magnesium in slightly alkaline medium. This reaction depends on adsorption of the dye on magnesium hydroxide. Ammonium ions reduce sensitivity of reaction.

Clebopride is a dopamine antagonist drug with antiemetic and prokinetic properties used to treat functional gastrointestinal disorders. Chemically, it is a substituted benzamide, closely related to metoclopramide.

Benzanthrone is an aromatic hydrocarbon derivate used as a dyestuff intermediate for anthraquinone-based dyes. It has the appearance of a light yellow to brown-green powder with melting point of 170 °C. It is insoluble in water and soluble in alcohol.

Sulpiride is a first generation, or typical antipsychotic drug of the benzamide class used mainly in the treatment of psychosis associated with schizophrenia and major depressive disorder.

Dazopride is an antiemetic and gastroprokinetic agent of the benzamide. It acts as a 5-HT3 receptor antagonist and 5-HT4 receptor agonist. In addition to its gastrointestinal effects, dazopride facilitates learning and memory in mice.

Nemonapride is a atypical antipsychotic used for the treatment of schizophrenia. Nemonapride acts as a D2 and D3 receptor antagonist, and is also a potent 5-HT1A receptor agonist. It has affinity for sigma receptors.

Azelaic acid is an organic compound with the formula (CH₂)₇(CO₂H)₂. This saturated dicarboxylic acid exists as a white powder. It is found in wheat, rye, and barley. It is a component of a number of hair and skin conditioners.