The use of long-lifetime emitting lanthanide(III) chelate labels or probes together with time-resolved fluorometry in detection provides a method to generate sensitive bioaffinity assays. However, the use of stable chelates demands very complicated optimization of the chelate structure. A great number of chelates have been synthesized, but usually, only the most prominent structures were then converted to corresponding biomolecule labeling reactants. This review covers the syntheses of luminescent lanthanide chelates comprising a pyridine subunit that allow solution and solid-phase bioconjugation.