Abstract Expressionism was a movement of aggressive, declaratory styles: Kline’s slashes, Newman’s “zips,” Rothko’s luminous pools of color. Artists with a more equivocal or lyrical approach, such as Jack Tworkov and Esteban Vicente, are today often considered second-tier members of the movement. Is forcefulness of attack necessarily the same as intensity of expression? Exhibitions of the two latter artists’ work invite us to reconsider.

Tworkov (1900–82) befriended Willem de Kooning during the WPA’s Federal Work Project, and later co-founded “The Club,” the debating center for New York School artists in the ’50s. The titles of Tworkov’s eight paintings at Mitchell-Innes & Nash reflect his interest in jazz, and they show the striking evolution of his attitude during the 15 years covered by the exhibition. The two earliest canvases, “Duo I” and “Duo II” (both 1956), borrow — all too cautiously — from de Kooning’s fractured figural compositions of the early ’50s. While de Kooning continuously revamped his figures in broad spasms, Tworkov fine-tunes with wispy marks.

“Blue Note” (1959), though, suggests an artist finding his authentic voice. In this vertical abstraction, brusque, flamelike reds reach yearningly into a zone of churning blues and blacks above. “5-Spot” (1960) too emits a confident, romantic energy. Here, a broad red wedge at the bottom and a dark blue above become the proscenium for a clutch of wide strokes — black slashes, layered over white ones — tilting with quixotic intensity.

In later years, Tworkov’s structures became more theoretical and linear, eventually turning into crisp, polygonal patterns. None of these appears in the exhibition, but “Nightfall” (1961) hints at a grid, with brushy patches of ochre, umber, and red enclosed in a quadrilateral framework. Painted eight years later, “Note” and “Idling” (both 1969) feature small black brushstrokes arranged in regular tiers on gray fields. By now, all dynamic oppositions are banished, and, for me, the captive, busy textures jar with their austere designs.

Don’t miss the small, untitled watercolor (c. 1960–62) that catches a fortuitous midpoint in the artist’s life after he had shaken de Kooning’s shadow and before he had settled into the comforts of theory. Conception and execution seem simultaneous for this sketch of blue and ochre washes shimmering behind a lively march of dark verticals. At this moment, the artist seems perfectly comfortable with his own earnest impulses.

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“I am considered an American painter yet my culture is Spanish forever,” Esteban Vicente (1903–2001) told an interviewer in 1998, and the proud individualism of these words shows in his distinctive contribution to Abstract Expressionism. Although Vicente was well-acquainted with the other New York School painters, especially de Kooning (who at one point had an adjacent studio), his work is unique for radiant but reserved lyricism.

His 13 paintings, collages, and drawings at Ameringer & Yohe span nearly 50 years. The earliest here, two abstract paintings from 1950 (“No. 24” and an untitled canvas) are de Kooning–esque in their brisk, fragmented modeling, but Vicente’s rounding rhythms and elegant colors suggest a wholly different attitude, one of gratified inquiry rather than torturous probing.

A gifted colorist, Vicente invigorates the intervals of a painting like “No. 1” (1961), so that a heavy burnt sienna huddles at a lower edge, a ragged pink sails buoyantly above, and the space in-between — an acidic greenish ochre — becomes elasticized by their pressures. After 1949, he regularly experimented with collage, producing works like “Ochre, White, Gray and Blue” (1961), in which a staunch, squarish blue anchors a dark yellow that stretches through a field of grays and whites; tangibly distant, its tip finally looks back.

Vicente claimed an affinity to the sober visions of Zurbarán and Juan Gris, and indeed, throughout this exhibition he elicits a raw grace from simple materials, his forms accumulating, if not with the inexorable speed of de Kooning’s strongest work, with its own poetic expansiveness.

The artist used a spray gun to produce two of the later paintings at Ameringer & Yohe. Some viewers may find their handsome, veiled colors a bit too proficiently seductive. Happily, the artist (in his mid-90s) returned to his brushes with “Country Side” (1997), a canvas that exalts with its rhythms rather than its technique. At its center, a heated red, thinly painted but weighty, rests on a crusty ochre, with lighter elements slipping spaciously away above and below.

One sometimes misses in both Vicente’s and Tworkov’s work the fretful, into-the-void urgency of the “first-tier” Abstract–Expressionists. But on the evidence of their work, Vicente never subscribed to this version of Ab-Ex, and Tworkov did so only fitfully. Both artists in the long run were simply true to themselves, and these exhibitions poignantly show them pursuing their necessary, independent paths.

Tworkov until March 30 (1018 Madison Ave., between 78th and 79th streets, 212-744-7400);

Vicente until March 17 (20 W. 57th St., between Fifth and Sixth avenues, 212-445-0051).