Motivated by a ``monoidal Yoneda's lemma'' we will study formal category theory in a ``double-dimensional'' setting. More precisely, where usually a 2-category is taken as setting, we instead take an ``(fc, bl)-multicategory'' as setting. The latter notion extends slightly that of fc-multicategory (aka virtual double category). After having introduced (fc, bl)-multicategories, in this first talk we consider their basic theory.