Methods are disclosed for determining an analyte in a medium suspected of containing the analyte. One method comprises providing (1) combining a medium suspected of containing the analyte and a novel chemiluminescent compound, (2) combining a means for chemically activating the chemiluminescent compound; and (3) detecting the amount of luminescence generated by the chemiluminescent compound. The amount of luminescence generated is related to the amount of analyte in the medium. The chemiluminescent compound can be chemically activated by hydrogen peroxide. Compositions and kits are also disclosed. The chemiluminescent compound is a spiro-acridan and has ##STR1## where X and Y are independently O, S, Se or NH; and Z is a chain, 1-5 atoms in length; 0 to 8 hydrogens of the compound alone or taken together, may be replaced an alkyl, alkylidine, aryl, aralkyl, or an alkyl, aryl or aralkyl substituted with one or more radicals of functional groups; 1 to 4 of the aromatic carbon atoms may be replaced by nitrogen atoms; and 0 to 1 hydrogens may be replaced by a specific binding pair member or fluorescent group.