Enhanced deposition of chromogens utilizing pyrimidine analogs

A method for detecting a target in a sample by proximally depositing a detectable moiety, comprising:

• contacting the sample with a recognition solution, the recognition solution including a specific binding moiety specific to the target;
• labeling the specific binding moiety with an enzyme;
• contacting the sample with a detection solution, the detection solution comprising an enzymatic substrate so that the detectable moiety deposits proximally to the target in the presence of a first deposition enhancer and a second deposition enhancer, the first deposition enhancer having a formula
• wherein R1, R2, R3, and R4 are independently selected from aliphatic, aryl, halogen, a heteroatom-containing moiety, and hydrogen;
• R1 and/or R3 can be bound to R2 to form a fused, aromatic ring system;
• R5 is a heteroatom-containing moiety;
• A is carbon, a heteroatom other than sulfur, and any combination thereof;
• and n is 1-5;
• and
• detecting the detectable moiety.