Enhanced deposition using chromogenic pyrimidine analogs

A method for detecting a target in a sample by depositing a proximal marker, comprising: contacting the sample with a solution of recognition, including recognition solution one specific binding moiety which is specific for the target; mark the specific binding moiety with an enzyme; contacting the sample with a detection solution, the solution of an enzyme substrate detection so that the marker is deposited proximally to the target in the presence of a deposition enhancer having a formula ** ** in Formula comprising R1, R2, R3 and R4 are independently selected from aliphatic group, aryl, halogen, a heteroatom containing moiety and hydrogen; R1 and / or R3 may be bonded to R2 to form a fused aromatic ring system; A is selected from a carbon atom, a different sulfur heteroatom and any combination thereof; and detecting the label.