"The Sophisticated Gents" is doubly refreshing, first in its subject and milieu and second in the opportunities it has given to a large cast of black actors and actresses to excel. Some of these performers do appear on television regularly, but usually as cops or crooks in subordinate roles on one dreary series or another.

For them, and for everybody, Melvin Van Peebles wrote a four-hour drama (starting with a two-hour chapter tonight at 9 on Channel 4, continuing Wednesday and Thursday at 10) that is heavily populated with dimensional, vulnerable, distinctive characters. Cheers for this Daniel Wilson Production should probably be tempered, however, with the suspicion that all these black performers were put into one big show so as to get that obligation out of the way early in the TV season.

Then, back to business as usual, with blacks mainly in cartoon comedy roles, as helpmates to white stars in action shows, or in revivals of such bygones-that-should-be-bygones as the mammy stereotype on NBC's upcoming "Gimme a Break." There is a further discouraging fact: "Gents" was completed two years ago and has been sitting on the shelf at NBC, apparently unwatched by top executives, ever since.

Be all that as it may, it is gratifying to find so many exceptional actors involved in a story that is not in the limited sense about race or racial conflict; this has to do with people, as well as with cultural heritage, and the empathetic possibilities for viewers are innumerable.

Van Peebles based his script on a John A. Williams novel that hinges on a fairly blatant gimmick; members of a long-disbanded social club stage a reunion to honor the man who was their coach and mentor 25 years earlier. As the story unfolds and the characters take shape, we see the hypocrisies or self-delusions beneath carefully nurtured exteriors, the grand designs that were allowed to die, and the dreams that are still hanging on for dear life.

The Gents are reminded of how they may have failed the great expectations their coach had for them and they had for themselves, but the drama is not a downer in the style of "That Championship Season"; the characters don't learn that everything has been a lie.

Director Harry Falk has trouble finding the right cadence for this story at first, and some of the opening scenes seem hesitant or random, but eventually the narrative threads take hold, and the characters grow into vivid portrayals. There are almost too many to keep track of, but among the most prominent are Robert Hooks as a hard-driven executive at a troubling crossroads in his life; Raymond St. Jacques as a classical singer with a skeleton or two in his closet; Paul Winfield as a goodhearted lug who never left the home turf; and Van Peebles himself as Moon, a pimp on the lam.

Others in the cast include Bernie Casey, Rosey Grier, Ron O'Neal, the imposing Thalmus Rasulala and Dick Anthony Williams. Among the women in their lives are Rosalind Cash, Janet MacLachlan, Denise Nicholas and Ja'net Dubois. There are more interracial sexual relationships than viewers may be used to, but this is not a central issue of the screenplay, only one of its facts of life.

And to Van Peebles' credit, the film is about more than, as might be expected, male bonding and rites of manhood. It is about friendship and loyalty in more universal terms, and about accommodation, compromise and those precious lies we all tell ourselves. Much of what it says is worth saying or, in some cases, worth saying again.

It isn't the script so much as the performances, though, that bring the story to life. Any scene in which Grier appears tends to have a certain robust glow about it. Cash is especially affecting as a helplessly unfaithful wife. And Albert Hall casts true menace as Swoop, a cynical and corrupt young cop who has always resented his rejection by the Gents.

There are continuity problems, and some awkward junctures, and some things underexplained. But "Sophisticated Gents" has a feel for people that excuses most of its shortcomings. One is inclined to say that it's damn good and leave it at that.