Fluorescent polymeric materials containing lipid soluble rhodamine dyes

Fluorescent polymeric materials are disclosed comprising a polymeric particle and one or more lipid soluble rhodamine dyes, comprising the following core structure: wherein R11 and R15 are each H or are each F or Cl; R12, R13, and R14 are each H or are each F or Cl; and wherein at least one of R3', R3'', R6' and R6' is a (C4-C20) alkyl. The materials are especially useful in the preparation of multicolored microparticles, especially multicolored polystyrene microparticle, for use in the multiplexed analysis of a plurality of analytes in a single sample. When excited by a light source, the materials give off a unique emission based on the nature, concentration and ratio of the dyes therein. Methods of preparing and using said materials are also disclosed.