The present invention provides dyes, reactive dyes and labeled reagents that may be used in the detection or quantification of desirable target molecules, such as proteins and nucleic acids. Dyes are provided that may be used free in solution where the binding of the dye to the target molecule provides signal generation. Dyes are also provided that comprise reactive groups that may be used to attach the dyes to probes that will bind to desirable target molecules. The novel dyes of the present invention have been modified by the addition of charged and polar groups to provide beneficial properties.