The research took place in Israel. Unsubstituted 1,2-indanedione and a number of its mono-derivatives and dimethoxy-derivatives exhibited excellent properties as fluorogenic reagents for latent fingerprints on paper. Structural modifications such as substitutions at position 3, omission of the benzene ring, or increase of the five-membered to a six-membered ring, considerably reduced this activity. A surprising finding was that denzo(f)indane-1,2-dione, which was synthesized for the first time in this research, was significantly inferior to 1,2-indanedione as a fingerprint reagent. Findings indicated that some 1,2-indanediones are at least as sensitive as 1,8-diazofluorene-9-one. Their solubility in nonpolar solvents and their relative ease of preparation are further advantages. Findings suggested that 1,2-indanedione itself may soon become a practical fingerprint reagent. Tables, photograph, and 14 references (Author abstract modified)