In some music, of a certain vintage — the precise vintage we'll leave to musicologists to fight out — the notational convention was that if one voice had eighth-note triplets, a simultaneous voice sounding quarter + eighth triplets could be written out as dotted-eighth + sixteenth. At some point — again, musicologists: have at it, this is your job, not mine — this convention gave way to a more logically consistant — if less stylish — reading of both triplets and dotted note values, so that the same notated rhythmic ensemble would have the sixteenth following the dotted eighth played one twelfth of a quarter note later than the last note in the triplet. As a piece of practical advice, consider this: Unless you specify the earlier convention in your scores, which may be musically useful, players will now expect the later reading.
Now a piece of aesthetic advice. As always, YMMV: be careful when superimposing additive and divisive note values. While such combinations may be useful — as a written-out rubato (a la Skryabin/Messiaen/Wyschnegradsky/Boulez), for example, or as transitional figures within some larger rhythmic process, or for adding to the contrast and independence of lines in ensemble counterpoint — there is risk, in just plopping some dotted-somethings on top of tuplets, of the combination coming out a bit clunky (see above). I don't have anything against clunky as a possible musical topic, but you don't always want clunky and it's often easy to confuse facile clunkiness with something more interesting.