The present invention relates to a chemical compound or a salt or solvate thereof being a phenazine-, phenanthridine-, phenanthroline-, quinoline-, quinoxaline-, acridine-isoquinoline-, pyrazine- or pyridine-derivative comprising a conjugated π-system and a π-acceptor group, and to uses thereof. The present invention further relates to a chemistry matrix and to a test element comprising the chemical compound of the present invention. The present invention also relates to a method of determining the amount of an analyte in a test sample, comprising contacting said test sample with a chemical compound, with a chemistry matrix, or with a test element of the invention and estimating the amount of redox equivalents liberated or consumed by the chemical compound, by the chemical compound comprised in said chemistry matrix, or by the chemical compound comprised in said test element, in the presence of said test sample, thereby determining the amount of an analyte in said test sample. Moreover, the present invention relates to a system comprising a test element according to the present invention and a device comprising a sensor for measuring the amount of redox equivalents liberated or consumed.