2-Nitrophenyl-β-D-galactopyranoside or ONPG is a chromogenic substrate for β-galactosidase. Upon hydrolysis, ONPG releases galactose along with a chromogenic yellow compound. Additionally, ONPG is a substrate useful for the determination of β-glucosidases.

2-O-Dodecylglycerol is both a reagent for chemical synthesis and a detergent for lysing cell membranes.

2-Phthalaldehyde (OPA) is a dialdehyde with a variety of uses. As a reagent it is used in sensitive fluorescent assays for amines or sulfhydryls, reacting above their isoelectric point in the presence of thiols and causing fluorescent emission. In high-performance liquid chromatographic separation OPA is used to derivatize amino acids and cytometric measurements of protein thiol groups. OPA also functions as a high-level disinfectant used to sterilize surgical tools and medical instruments.

2-thiouracil is a sulfated uracil typically used as an anti-thyroid agent for Graves’ disease by inhibiting the thyroid enzyme thyroid peroxidase. When given to lab animals it can induce arteriosclerosis.

28-homo-brassinolide is a plant hormone from a class of polyhydroxysteroids that has been shown to have a protective role in plants under various stress situations; showing significant improvement of plant growth, water uptake, photosynthesis and yield. 28-homo-brassinolide has been shown to be the most effective of any of the brassinosteroids in mitigating plant stress effects from natural conditions such as chilling, drought, heat or salinity.

Brassinosteriods are a group of plant hormones that occur naturally in the plant kingdom. They have a variety of physiological roles including cell division and elongation, gene regulation, photosynthesis, senescence, enzyme activation and growth.

3,4-Cyclohexenoesculetin beta-D-galactopyranoside is a chromatographic reagent for selective isolation of Salmonella spp.

3,5-Dichloro-2-hydroxybenzenesulfonic acid, disodium salt is a reagent used to produce peroxides when combined with 4-aminoantipyrine. It is also used in quantification of hydrogen peroxide through horseradish peroxidase-mediated conversion of itself and 4-aminoantipyrine to a colored product. Under this principle, it is used to determine uric acid in serum as oxidation of uric acid in a uricase-catalyzed reaction yields hydrogen peroxide.

3,5-Diiodo-L-tyrosine dehydrate is an a substrate in the assay of halogenated tyrosine and thyroid hormones aminotransferase. It is also an intermediate in the synthesis and pathways of thyroid hormone metabolism.