摘要： With the development of life science,there is a grow ing requirement for high sensit ive detect ion technolog ies in analysis.Fluorescence label is a convenient method.Indocyanines with larger ex tinction coefficients(10⁵L/mol cm),good fluorescent proper ties and fluorescence enhancement combining with biomass have been used as a new generation of fluorescent label compounds in biological analysis.How ever,photostability of these dyes has been a problem.In this paper the substituents on the nitro gen atoms in the heterocyclic rings of these indo-cyanines were designed as p-carbox ybenzyl groups,and ser ies novel straight chain polymet hine indocyanines w ere synthesized.Introduction of rigid rings into the methine chain resulted in other series novel 3H-indocya-nines.