Carbohydrates conjugated with 2-chloro-4-nitrophenyl (CNP) serve as chromogenic substrates in assays for enzymes that release CNP from the conjugated carbohydrate. For example, CNP-β-D-maltoheptaoside and CNP-α-maltotrioside are chromogenic substrates for α-amylase. 2-Chloro-4-nitrophenyl-α-D-glucopyranoside is a conjugate of CNP and α-D-glucose. The related conjugate between CNP and β-D-glucose, 2-chloro-4-nitrophenyl β-D-glucopyranoside, is used as a chromogenic substrate for glycosyltransferases. This product is a chromogenic substrate for enzymes that target the linkage between CNP and α-D-glucose.