Cyanines which selectively bind to G-quadruplex DNA complexes, particularly quadruplexes expressed in cancer cells, and methods of making and using thereof are described herein. The cyanine can be a symmetrical or unsymmetrical streptocyanine, hemicyanine, closed chain cyanine, or combinations thereof. The cyanine is preferably substituted with one or more groups that minimize or prevent aggregation of the cyanine and/or inhibit binding of the cyanine to duplex DNA. One or more of the cyanines can be formulated with one or more pharmaceutical excipients and/or carrier to prepare pharmaceutical compositions suitable for administration to a patient, particular a human patient. The compounds and compositions described herein can be used to treat diseases or disorders characterized by the expression of G-quadruplex DNA, such as cancer.