In strong-electroweak unification, based on SU(15), with baryon number (B) and lepton number (L) conserved, bosons with B = +/- 2/3, L = 0 (diquarks), B = 0, L = +/- 2 (dileptons) and B = +/- 1/3, L = +/- 1 (leptoquarks) can occur at "light" (less-than-or-equal-to TeV) scales. The discovery of light leptoquarks would be evidence as compelling as proton decay for grand unification.