A small subset of heptamethine dyes (cyanine-7 or Cy7) share an intriguing characteristic: preferential tumor accumulation and retention. These dyes absorb in the near-infrared (NIR) region (above 750 nm) and perform active targeting to deliver therapeutic and toxic cargoes to various tumor models in vivo. In this work, four heptamethines <b>1</b> were synthesized, which have a gemcitabine fragment attached to the <i>meso</i>-position of the Cy7 core. Theranostic agent <b>1a</b> was discovered that localized in glioblastoma tumor cells, has absorption maxima in NIR region, and showed similar therapeutic effect to gemcitabine but at one-third the molar dose.